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Message-ID: <20231113035219.920136-9-chopps@chopps.org>
Date: Sun, 12 Nov 2023 22:52:19 -0500
From: Christian Hopps <chopps@...pps.org>
To: devel@...ux-ipsec.org
Cc: Steffen Klassert <steffen.klassert@...unet.com>,
netdev@...r.kernel.org,
Christian Hopps <chopps@...pps.org>,
Christian Hopps <chopps@...n.net>
Subject: [RFC ipsec-next v2 8/8] iptfs: impl: add new iptfs xfrm mode impl
From: Christian Hopps <chopps@...n.net>
Add a new xfrm mode implementing AggFrag/IP-TFS from RFC9347.
This utilizes the new xfrm_mode_cbs to implement demand-driven IP-TFS
functionality. This functionality can be used to increase bandwidth
utilization through small packet aggregation, as well as help solve PMTU
issues through it's efficient use of fragmentation.
Link: https://www.rfc-editor.org/rfc/rfc9347.txt
Signed-off-by: Christian Hopps <chopps@...n.net>
---
include/net/iptfs.h | 18 +
net/xfrm/Makefile | 1 +
net/xfrm/trace_iptfs.h | 224 ++++
net/xfrm/xfrm_iptfs.c | 2696 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 2939 insertions(+)
create mode 100644 include/net/iptfs.h
create mode 100644 net/xfrm/trace_iptfs.h
create mode 100644 net/xfrm/xfrm_iptfs.c
diff --git a/include/net/iptfs.h b/include/net/iptfs.h
new file mode 100644
index 000000000000..d8f2e494f251
--- /dev/null
+++ b/include/net/iptfs.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_IPTFS_H
+#define _NET_IPTFS_H
+
+#include <linux/types.h>
+#include <linux/ip.h>
+
+#define IPTFS_SUBTYPE_BASIC 0
+#define IPTFS_SUBTYPE_CC 1
+#define IPTFS_SUBTYPE_LAST IPTFS_SUBTYPE_CC
+
+#define IPTFS_CC_FLAGS_ECN_CE 0x1
+#define IPTFS_CC_FLAGS_PLMTUD 0x2
+
+extern void xfrm_iptfs_get_rtt_and_delays(struct ip_iptfs_cc_hdr *cch, u32 *rtt,
+ u32 *actual_delay, u32 *xmit_delay);
+
+#endif /* _NET_IPTFS_H */
diff --git a/net/xfrm/Makefile b/net/xfrm/Makefile
index cd47f88921f5..9b870a3274a7 100644
--- a/net/xfrm/Makefile
+++ b/net/xfrm/Makefile
@@ -20,4 +20,5 @@ obj-$(CONFIG_XFRM_USER) += xfrm_user.o
obj-$(CONFIG_XFRM_USER_COMPAT) += xfrm_compat.o
obj-$(CONFIG_XFRM_IPCOMP) += xfrm_ipcomp.o
obj-$(CONFIG_XFRM_INTERFACE) += xfrm_interface.o
+obj-$(CONFIG_XFRM_IPTFS) += xfrm_iptfs.o
obj-$(CONFIG_XFRM_ESPINTCP) += espintcp.o
diff --git a/net/xfrm/trace_iptfs.h b/net/xfrm/trace_iptfs.h
new file mode 100644
index 000000000000..994b6dafd1ef
--- /dev/null
+++ b/net/xfrm/trace_iptfs.h
@@ -0,0 +1,224 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* xfrm_trace_iptfs.h
+ *
+ * August 12 2023, Christian Hopps <chopps@...n.net>
+ *
+ * Copyright (c) 2023, LabN Consulting, L.L.C.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM iptfs
+
+#if !defined(_TRACE_IPTFS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_IPTFS_H
+
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/tracepoint.h>
+#include <net/ip.h>
+
+struct xfrm_iptfs_data;
+
+TRACE_EVENT(iptfs_egress_recv,
+ TP_PROTO(struct sk_buff *skb, struct xfrm_iptfs_data *xtfs, u16 blkoff),
+ TP_ARGS(skb, xtfs, blkoff),
+ TP_STRUCT__entry(
+ __field(struct sk_buff *, skb)
+ __field(void *, head)
+ __field(void *, head_pg_addr)
+ __field(void *, pg0addr)
+ __field(u32, skb_len)
+ __field(u32, data_len)
+ __field(u32, headroom)
+ __field(u32, tailroom)
+ __field(u32, tail)
+ __field(u32, end)
+ __field(u32, pg0off)
+ __field(u8, head_frag)
+ __field(u8, frag_list)
+ __field(u8, nr_frags)
+ __field(u16, blkoff)),
+ TP_fast_assign(
+ __entry->skb = skb;
+ __entry->head = skb->head;
+ __entry->skb_len = skb->len;
+ __entry->data_len = skb->data_len;
+ __entry->headroom = skb_headroom(skb);
+ __entry->tailroom = skb_tailroom(skb);
+ __entry->tail = skb->tail;
+ __entry->end = skb->end;
+ __entry->head_frag = skb->head_frag;
+ __entry->frag_list = (bool)skb_shinfo(skb)->frag_list;
+ __entry->nr_frags = skb_shinfo(skb)->nr_frags;
+ __entry->blkoff = blkoff;
+ __entry->head_pg_addr = page_address(virt_to_head_page(skb->head));
+ __entry->pg0addr = (__entry->nr_frags
+ ? page_address(skb_shinfo(skb)->frags[0].bv_page)
+ : 0);
+ __entry->pg0off = (__entry->nr_frags ? skb_shinfo(skb)->frags[0].bv_offset : 0);
+
+ ),
+ TP_printk("EGRESS: skb=%p len=%u data_len=%u headroom=%u head_frag=%u frag_list=%u nr_frags=%u blkoff=%u\n\t\ttailroom=%u tail=%u end=%u head=%p hdpgaddr=%p pg0->addr=%p pg0->data=%p pg0->off=%u",
+ __entry->skb, __entry->skb_len, __entry->data_len, __entry->headroom,
+ __entry->head_frag, __entry->frag_list, __entry->nr_frags, __entry->blkoff,
+ __entry->tailroom, __entry->tail, __entry->end, __entry->head,
+ __entry->head_pg_addr, __entry->pg0addr, __entry->pg0addr + __entry->pg0off,
+ __entry->pg0off)
+ )
+
+DECLARE_EVENT_CLASS(iptfs_ingress_preq_event,
+ TP_PROTO(struct sk_buff *skb, struct xfrm_iptfs_data *xtfs,
+ u32 pmtu, u8 was_gso),
+ TP_ARGS(skb, xtfs, pmtu, was_gso),
+ TP_STRUCT__entry(
+ __field(struct sk_buff *, skb)
+ __field(u32, skb_len)
+ __field(u32, data_len)
+ __field(u32, pmtu)
+ __field(u32, queue_size)
+ __field(u32, proto_seq)
+ __field(u8, proto)
+ __field(u8, was_gso)
+ ),
+ TP_fast_assign(
+ __entry->skb = skb;
+ __entry->skb_len = skb->len;
+ __entry->data_len = skb->data_len;
+ __entry->queue_size = xtfs->cfg.max_queue_size - xtfs->queue_size;
+ __entry->proto = __trace_ip_proto(ip_hdr(skb));
+ __entry->proto_seq = __trace_ip_proto_seq(ip_hdr(skb));
+ __entry->pmtu = pmtu;
+ __entry->was_gso = was_gso;
+ ),
+ TP_printk("INGRPREQ: skb=%p len=%u data_len=%u qsize=%u proto=%u proto_seq=%u pmtu=%u was_gso=%u",
+ __entry->skb, __entry->skb_len, __entry->data_len,
+ __entry->queue_size, __entry->proto, __entry->proto_seq,
+ __entry->pmtu, __entry->was_gso));
+
+DEFINE_EVENT(iptfs_ingress_preq_event, iptfs_enqueue,
+ TP_PROTO(struct sk_buff *skb, struct xfrm_iptfs_data *xtfs, u32 pmtu, u8 was_gso),
+ TP_ARGS(skb, xtfs, pmtu, was_gso));
+
+DEFINE_EVENT(iptfs_ingress_preq_event, iptfs_no_queue_space,
+ TP_PROTO(struct sk_buff *skb, struct xfrm_iptfs_data *xtfs, u32 pmtu, u8 was_gso),
+ TP_ARGS(skb, xtfs, pmtu, was_gso));
+
+DEFINE_EVENT(iptfs_ingress_preq_event, iptfs_too_big,
+ TP_PROTO(struct sk_buff *skb, struct xfrm_iptfs_data *xtfs, u32 pmtu, u8 was_gso),
+ TP_ARGS(skb, xtfs, pmtu, was_gso));
+
+DECLARE_EVENT_CLASS(
+ iptfs_ingress_postq_event,
+ TP_PROTO(struct sk_buff *skb, u32 mtu, u16 blkoff, struct iphdr *iph),
+ TP_ARGS(skb, mtu, blkoff, iph),
+ TP_STRUCT__entry(__field(struct sk_buff *, skb)
+ __field(u32, skb_len)
+ __field(u32, data_len)
+ __field(u32, mtu)
+ __field(u32, proto_seq)
+ __field(u16, blkoff)
+ __field(u8, proto)),
+ TP_fast_assign(__entry->skb = skb;
+ __entry->skb_len = skb->len;
+ __entry->data_len = skb->data_len;
+ __entry->mtu = mtu;
+ __entry->blkoff = blkoff;
+ __entry->proto = iph ? __trace_ip_proto(iph) : 0;
+ __entry->proto_seq = iph ? __trace_ip_proto_seq(iph) : 0;
+ ),
+ TP_printk(
+ "INGRPSTQ: skb=%p len=%u data_len=%u mtu=%u blkoff=%u proto=%u proto_seq=%u",
+ __entry->skb, __entry->skb_len, __entry->data_len, __entry->mtu,
+ __entry->blkoff, __entry->proto, __entry->proto_seq));
+
+DEFINE_EVENT(iptfs_ingress_postq_event, iptfs_first_dequeue,
+ TP_PROTO(struct sk_buff *skb, u32 mtu, u16 blkoff,
+ struct iphdr *iph),
+ TP_ARGS(skb, mtu, blkoff, iph));
+
+DEFINE_EVENT(iptfs_ingress_postq_event, iptfs_first_fragmenting,
+ TP_PROTO(struct sk_buff *skb, u32 mtu, u16 blkoff,
+ struct iphdr *iph),
+ TP_ARGS(skb, mtu, blkoff, iph));
+
+DEFINE_EVENT(iptfs_ingress_postq_event, iptfs_first_final_fragment,
+ TP_PROTO(struct sk_buff *skb, u32 mtu, u16 blkoff,
+ struct iphdr *iph),
+ TP_ARGS(skb, mtu, blkoff, iph));
+
+DEFINE_EVENT(iptfs_ingress_postq_event, iptfs_first_toobig,
+ TP_PROTO(struct sk_buff *skb, u32 mtu, u16 blkoff,
+ struct iphdr *iph),
+ TP_ARGS(skb, mtu, blkoff, iph));
+
+TRACE_EVENT(iptfs_ingress_nth_peek,
+ TP_PROTO(struct sk_buff *skb, u32 remaining),
+ TP_ARGS(skb, remaining),
+ TP_STRUCT__entry(__field(struct sk_buff *, skb)
+ __field(u32, skb_len)
+ __field(u32, remaining)),
+ TP_fast_assign(__entry->skb = skb;
+ __entry->skb_len = skb->len;
+ __entry->remaining = remaining;
+ ),
+ TP_printk("INGRPSTQ: NTHPEEK: skb=%p len=%u remaining=%u",
+ __entry->skb, __entry->skb_len, __entry->remaining));
+
+TRACE_EVENT(iptfs_ingress_nth_add, TP_PROTO(struct sk_buff *skb, u8 share_ok),
+ TP_ARGS(skb, share_ok),
+ TP_STRUCT__entry(__field(struct sk_buff *, skb)
+ __field(u32, skb_len)
+ __field(u32, data_len)
+ __field(u8, share_ok)
+ __field(u8, head_frag)
+ __field(u8, pp_recycle)
+ __field(u8, cloned)
+ __field(u8, shared)
+ __field(u8, nr_frags)
+ __field(u8, frag_list)
+ ),
+ TP_fast_assign(__entry->skb = skb;
+ __entry->skb_len = skb->len;
+ __entry->data_len = skb->data_len;
+ __entry->share_ok = share_ok;
+ __entry->head_frag = skb->head_frag;
+ __entry->pp_recycle = skb->pp_recycle;
+ __entry->cloned = skb_cloned(skb);
+ __entry->shared = skb_shared(skb);
+ __entry->nr_frags = skb_shinfo(skb)->nr_frags;
+ __entry->frag_list = (bool)skb_shinfo(skb)->frag_list;
+ ),
+ TP_printk("INGRPSTQ: NTHADD: skb=%p len=%u data_len=%u share_ok=%u head_frag=%u pp_recycle=%u cloned=%u shared=%u nr_frags=%u frag_list=%u",
+ __entry->skb, __entry->skb_len, __entry->data_len, __entry->share_ok,
+ __entry->head_frag, __entry->pp_recycle, __entry->cloned, __entry->shared,
+ __entry->nr_frags, __entry->frag_list));
+
+DECLARE_EVENT_CLASS(iptfs_timer_event,
+ TP_PROTO(struct xfrm_iptfs_data *xtfs, u64 time_val),
+ TP_ARGS(xtfs, time_val),
+ TP_STRUCT__entry(
+ __field(u64, time_val)
+ __field(u64, set_time)),
+ TP_fast_assign(
+ __entry->time_val = time_val;
+ __entry->set_time = xtfs->iptfs_settime;
+ ),
+ TP_printk("TIMER: set_time=%llu time_val=%llu",
+ __entry->set_time, __entry->time_val));
+
+DEFINE_EVENT(iptfs_timer_event, iptfs_timer_start,
+ TP_PROTO(struct xfrm_iptfs_data *xtfs, u64 time_val),
+ TP_ARGS(xtfs, time_val));
+
+DEFINE_EVENT(iptfs_timer_event, iptfs_timer_expire,
+ TP_PROTO(struct xfrm_iptfs_data *xtfs, u64 time_val),
+ TP_ARGS(xtfs, time_val));
+
+#endif /* _TRACE_IPTFS_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../net/xfrm
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace_iptfs
+#include <trace/define_trace.h>
diff --git a/net/xfrm/xfrm_iptfs.c b/net/xfrm/xfrm_iptfs.c
new file mode 100644
index 000000000000..65f7acdbe6a8
--- /dev/null
+++ b/net/xfrm/xfrm_iptfs.c
@@ -0,0 +1,2696 @@
+// SPDX-License-Identifier: GPL-2.0
+/* xfrm_iptfs: IPTFS encapsulation support
+ *
+ * April 21 2022, Christian Hopps <chopps@...n.net>
+ *
+ * Copyright (c) 2022, LabN Consulting, L.L.C.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/icmpv6.h>
+#include <net/gro.h>
+#include <net/icmp.h>
+#include <net/ip6_route.h>
+#include <net/inet_ecn.h>
+#include <net/iptfs.h>
+#include <net/xfrm.h>
+
+#include <crypto/aead.h>
+
+#include "xfrm_inout.h"
+#include "trace_iptfs.h"
+
+/* 1) skb->head should be cache aligned.
+ * 2) when resv is for L2 headers (i.e., ethernet) we want the cacheline to
+ * start -16 from data.
+ * 3) when resv is for L3+L2 headers IOW skb->data points at the IPTFS payload
+ * we want data to be cache line aligned so all the pushed headers will be in
+ * another cacheline.
+ */
+#define XFRM_IPTFS_MIN_L3HEADROOM 128
+#define XFRM_IPTFS_MIN_L2HEADROOM (64 + 16)
+#define IPTFS_FRAG_COPY_MAX 256 /* max for copying to create iptfs frags */
+#define IPTFS_PKT_SHARE_MIN 129 /* min to try to share vs copy pkt data */
+#define NSECS_IN_USEC 1000
+
+#define IPTFS_TYPE_NOCC 0
+#define IPTFS_TYPE_CC 1
+
+#define IPTFS_HRTIMER_MODE HRTIMER_MODE_REL_SOFT
+
+struct skb_wseq {
+ struct sk_buff *skb;
+ u64 drop_time;
+};
+
+struct xfrm_iptfs_config {
+ bool dont_frag : 1;
+ u16 reorder_win_size;
+ u32 pkt_size; /* outer_packet_size or 0 */
+ u32 max_queue_size; /* octets */
+ u64 init_delay_us; /* microseconds */
+ u32 drop_time_us; /* microseconds */
+};
+
+struct xfrm_iptfs_data {
+ struct xfrm_iptfs_config cfg;
+
+ /* Ingress User Input */
+ struct xfrm_state *x; /* owning state */
+ struct sk_buff_head queue; /* output queue */
+ u32 queue_size; /* octets */
+ u32 ecn_queue_size; /* octets above which ECN mark */
+ u64 init_delay_ns; /* nanoseconds */
+ struct hrtimer iptfs_timer; /* output timer */
+ time64_t iptfs_settime; /* time timer was set */
+ u32 payload_mtu; /* max payload size */
+
+ /* Tunnel input reordering */
+ bool w_seq_set; /* true after first seq received */
+ u64 w_wantseq; /* expected next sequence */
+ struct skb_wseq *w_saved; /* the saved buf array */
+ u32 w_savedlen; /* the saved len (not size) */
+ spinlock_t drop_lock;
+ struct hrtimer drop_timer;
+ u64 drop_time_ns;
+
+ /* Tunnel input reassembly */
+ struct sk_buff *ra_newskb; /* new pkt being reassembled */
+ u64 ra_wantseq; /* expected next sequence */
+ u8 ra_runt[6]; /* last pkt bytes from last skb */
+ u8 ra_runtlen; /* count of ra_runt */
+};
+
+static u32 __iptfs_get_inner_mtu(struct xfrm_state *x, int outer_mtu);
+static enum hrtimer_restart iptfs_delay_timer(struct hrtimer *me);
+static enum hrtimer_restart iptfs_drop_timer(struct hrtimer *me);
+
+/* ================= */
+/* Utility Functions */
+/* ================= */
+
+static u32 __trace_ip_proto(struct iphdr *iph)
+{
+ if (iph->version == 4)
+ return iph->protocol;
+ return ((struct ipv6hdr *)iph)->nexthdr;
+}
+
+static u32 __trace_ip_proto_seq(struct iphdr *iph)
+{
+ void *nexthdr;
+ u32 protocol = 0;
+
+ if (iph->version == 4) {
+ nexthdr = (void *)(iph + 1);
+ protocol = iph->protocol;
+ } else if (iph->version == 6) {
+ nexthdr = (void *)(((struct ipv6hdr *)(iph)) + 1);
+ protocol = ((struct ipv6hdr *)(iph))->nexthdr;
+ }
+ switch (protocol) {
+ case IPPROTO_ICMP:
+ return ntohs(((struct icmphdr *)nexthdr)->un.echo.sequence);
+ case IPPROTO_ICMPV6:
+ return ntohs(((struct icmp6hdr *)nexthdr)->icmp6_sequence);
+ case IPPROTO_TCP:
+ return ntohl(((struct tcphdr *)nexthdr)->seq);
+ case IPPROTO_UDP:
+ return ntohs(((struct udphdr *)nexthdr)->source);
+ default:
+ return 0;
+ }
+}
+
+static u64 __esp_seq(struct sk_buff *skb)
+{
+ u64 seq = ntohl(XFRM_SKB_CB(skb)->seq.input.low);
+
+ return seq | (u64)ntohl(XFRM_SKB_CB(skb)->seq.input.hi) << 32;
+}
+
+/* ================= */
+/* SK_BUFF Functions */
+/* ================= */
+
+/**
+ * iptfs_alloc_skb() - Allocate a new `skb` using a meta-data template.
+ * @tpl: the template to copy the new `skb`s meta-data from.
+ * @len: the linear length of the head data, zero is fine.
+ * @l3resv: true if reserve needs to support pushing L3 headers
+ *
+ * A new `skb` is allocated and it's meta-data is initialized from `tpl`, the
+ * head data is sized to `len` + reserved space set according to the @l3resv
+ * boolean. When @l3resv is false, resv is XFRM_IPTFS_MIN_L2HEADROOM which
+ * arranges for `skb->data - 16` (etherhdr space) to be the start of a cacheline.
+ * Otherwise, @l3resv is true and resv is either the size of headroom from `tpl` or
+ * XFRM_IPTFS_MIN_L3HEADROOM whichever is greater, which tries to align
+ * skb->data to a cacheline as all headers will be pushed on the previous
+ * cacheline bytes.
+ *
+ * When copying meta-data from the @tpl, the sk_buff->headers are not copied.
+ *
+ * Zero length skbs are allocated when we only need a head skb to hold new
+ * packet headers (basically the mac header) that sit on top of existing shared
+ * packet data.
+ *
+ * Return: the new skb or NULL.
+ */
+static struct sk_buff *iptfs_alloc_skb(struct sk_buff *tpl, u32 len,
+ bool l3resv)
+{
+ struct sk_buff *skb;
+ u32 resv;
+
+ if (!l3resv) {
+ resv = XFRM_IPTFS_MIN_L2HEADROOM;
+ } else {
+ resv = skb_headroom(tpl);
+ if (resv < XFRM_IPTFS_MIN_L3HEADROOM)
+ resv = XFRM_IPTFS_MIN_L3HEADROOM;
+ }
+
+ skb = alloc_skb(len + resv, GFP_ATOMIC);
+ if (!skb) {
+ XFRM_INC_STATS(dev_net(tpl->dev), LINUX_MIB_XFRMINERROR);
+ return NULL;
+ }
+
+ skb_reserve(skb, resv);
+
+ /* Code from __copy_skb_header() -- we do not want any of the
+ * tpl->headers copied over, so we aren't using `skb_copy_header()`.
+ */
+ skb->tstamp = tpl->tstamp;
+ skb->dev = tpl->dev;
+ memcpy(skb->cb, tpl->cb, sizeof(skb->cb));
+ skb_dst_copy(skb, tpl);
+ __skb_ext_copy(skb, tpl);
+ __nf_copy(skb, tpl, false);
+
+ return skb;
+}
+
+/**
+ * skb_head_to_frag() - initialize a skb_frag_t based on skb head data
+ */
+static void skb_head_to_frag(const struct sk_buff *skb, skb_frag_t *frag)
+{
+ struct page *page = virt_to_head_page(skb->data);
+ unsigned char *addr = (unsigned char *)page_address(page);
+
+ BUG_ON(!skb->head_frag);
+ skb_frag_fill_page_desc(frag, page, skb->data - addr, skb_headlen(skb));
+}
+
+/**
+ * struct skb_frag_walk - use to track a walk through fragments
+ * @fragi: current fragment index
+ * @past: length of data in fragments before @fragi
+ * @total: length of data in all fragments
+ * @nr_frags: number of fragments present in array
+ * @initial_offset: the value passed in to skb_prepare_frag_walk()
+ * @pp_recycle: copy of skb->pp_recycle
+ * @frags: the page fragments inc. room for head page
+ */
+struct skb_frag_walk {
+ u32 fragi;
+ u32 past;
+ u32 total;
+ u32 nr_frags;
+ u32 initial_offset;
+ bool pp_recycle;
+ skb_frag_t frags[MAX_SKB_FRAGS + 1];
+};
+
+/**
+ * skb_prepare_frag_walk() - initialize a frag walk over an skb.
+ * @skb: the skb to walk.
+ * @initial_offset: start the walk @initial_offset into the skb.
+ * @walk: the walk to initialize
+ *
+ * Future calls to skb_add_frags() will expect the @offset value to be at
+ * least @initial_offset large.
+ */
+static void skb_prepare_frag_walk(struct sk_buff *skb, u32 initial_offset,
+ struct skb_frag_walk *walk)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ skb_frag_t *frag, *from;
+ u32 i;
+
+ walk->initial_offset = initial_offset;
+ walk->fragi = 0;
+ walk->past = 0;
+ walk->total = 0;
+ walk->nr_frags = 0;
+ walk->pp_recycle = skb->pp_recycle;
+
+ if (skb->head_frag) {
+ if (initial_offset >= skb_headlen(skb)) {
+ initial_offset -= skb_headlen(skb);
+ } else {
+ frag = &walk->frags[walk->nr_frags++];
+ skb_head_to_frag(skb, frag);
+ frag->bv_offset += initial_offset;
+ frag->bv_len -= initial_offset;
+ walk->total += frag->bv_len;
+ initial_offset = 0;
+ }
+ } else {
+ BUG_ON(skb_headlen(skb) > initial_offset);
+ initial_offset -= skb_headlen(skb);
+ }
+
+ for (i = 0; i < shinfo->nr_frags; i++) {
+ from = &shinfo->frags[i];
+ if (initial_offset >= from->bv_len) {
+ initial_offset -= from->bv_len;
+ continue;
+ }
+ frag = &walk->frags[walk->nr_frags++];
+ *frag = *from;
+ if (initial_offset) {
+ frag->bv_offset += initial_offset;
+ frag->bv_len -= initial_offset;
+ initial_offset = 0;
+ }
+ walk->total += frag->bv_len;
+ }
+ BUG_ON(initial_offset != 0);
+}
+
+static u32 __skb_reset_frag_walk(struct skb_frag_walk *walk, u32 offset)
+{
+ /* Adjust offset to refer to internal walk values */
+ BUG_ON(offset < walk->initial_offset);
+ offset -= walk->initial_offset;
+
+ /* Get to the correct fragment for offset */
+ while (offset < walk->past) {
+ walk->past -= walk->frags[--walk->fragi].bv_len;
+ if (offset >= walk->past)
+ break;
+ BUG_ON(walk->fragi == 0);
+ }
+ while (offset >= walk->past + walk->frags[walk->fragi].bv_len)
+ walk->past += walk->frags[walk->fragi++].bv_len;
+
+ /* offset now relative to this current frag */
+ offset -= walk->past;
+ return offset;
+}
+
+/**
+ * skb_can_add_frags() - check if ok to add frags from walk to skb
+ * @skb: skb to check for adding frags to
+ * @walk: the walk that will be used as source for frags.
+ * @offset: offset from beginning of original skb to start from.
+ * @len: amount of data to add frag references to in @skb.
+ */
+static bool skb_can_add_frags(const struct sk_buff *skb,
+ struct skb_frag_walk *walk, u32 offset, u32 len)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ u32 fragi, nr_frags, fraglen;
+
+ if (skb_has_frag_list(skb) || skb->pp_recycle != walk->pp_recycle)
+ return false;
+
+ /* Make offset relative to current frag after setting that */
+ offset = __skb_reset_frag_walk(walk, offset);
+
+ /* Verify we have array space for the fragments we need to add */
+ fragi = walk->fragi;
+ nr_frags = shinfo->nr_frags;
+ while (len && fragi < walk->nr_frags) {
+ skb_frag_t *frag = &walk->frags[fragi];
+
+ fraglen = frag->bv_len;
+ if (offset) {
+ fraglen -= offset;
+ offset = 0;
+ }
+ if (++nr_frags > MAX_SKB_FRAGS)
+ return false;
+ if (len <= fraglen)
+ return true;
+ len -= fraglen;
+ fragi++;
+ }
+ /* We may not copy all @len but what we have will fit. */
+ return true;
+}
+
+/**
+ * skb_add_frags() - add a range of fragment references into an skb
+ * @skb: skb to add references into
+ * @walk: the walk to add referenced fragments from.
+ * @offset: offset from beginning of original skb to start from.
+ * @len: amount of data to add frag references to in @skb.
+ *
+ * skb_can_add_frags() should be called before this function to verify that the
+ * destination @skb is compatible with the walk and has space in the array for
+ * the to be added frag refrences.
+ *
+ * Return: The number of bytes not added to @skb b/c we reached the end of the
+ * walk before adding all of @len.
+ */
+static int skb_add_frags(struct sk_buff *skb, struct skb_frag_walk *walk,
+ u32 offset, u32 len)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ u32 fraglen;
+
+ BUG_ON(skb->pp_recycle != walk->pp_recycle);
+ if (!walk->nr_frags || offset >= walk->total + walk->initial_offset)
+ return len;
+
+ /* make offset relative to current frag after setting that */
+ offset = __skb_reset_frag_walk(walk, offset);
+ BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
+
+ while (len && walk->fragi < walk->nr_frags) {
+ skb_frag_t *frag = &walk->frags[walk->fragi];
+ skb_frag_t *tofrag = &shinfo->frags[shinfo->nr_frags];
+
+ *tofrag = *frag;
+ if (offset) {
+ tofrag->bv_offset += offset;
+ tofrag->bv_len -= offset;
+ offset = 0;
+ }
+ __skb_frag_ref(tofrag);
+ shinfo->nr_frags++;
+ BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
+
+ /* see if we are done */
+ fraglen = tofrag->bv_len;
+ if (len < fraglen) {
+ tofrag->bv_len = len;
+ skb->len += len;
+ skb->data_len += len;
+ return 0;
+ }
+ /* advance to next source fragment */
+ len -= fraglen; /* careful, use dst bv_len */
+ skb->len += fraglen; /* careful, " " " */
+ skb->data_len += fraglen; /* careful, " " " */
+ walk->past +=
+ frag->bv_len; /* careful, use src bv_len */
+ walk->fragi++;
+ }
+ return len;
+}
+
+/**
+ * skb_copy_bits_seq - copy bits from a skb_seq_state to kernel buffer
+ * @st: source skb_seq_state
+ * @offset: offset in source
+ * @to: destination buffer
+ * @len: number of bytes to copy
+ *
+ * Copy @len bytes from @offset bytes into the source @st to the destination
+ * buffer @to. `offset` should increase (or be unchanged) with each subsequent
+ * call to this function. If offset needs to decrease from the previous use `st`
+ * should be reset first.
+ */
+static int skb_copy_bits_seq(struct skb_seq_state *st, int offset, void *to, int len)
+{
+ const u8 *data;
+ u32 sqlen;
+
+ for (;;) {
+ sqlen = skb_seq_read(offset, &data, st);
+ if (sqlen == 0)
+ return -ENOMEM;
+ if (sqlen >= len) {
+ memcpy(to, data, len);
+ return 0;
+ }
+ memcpy(to, data, sqlen);
+ to += sqlen;
+ offset += sqlen;
+ len -= sqlen;
+ }
+}
+
+/* ================================== */
+/* IPTFS Trace Event Definitions */
+/* ================================== */
+
+#define CREATE_TRACE_POINTS
+#include "trace_iptfs.h"
+
+/* ================================== */
+/* IPTFS Receiving (egress) Functions */
+/* ================================== */
+
+/**
+ * iptfs_pskb_add_frags() - Create and add frags into a new sk_buff.
+ * @tpl: template to create new skb from.
+ * @walk: The source for fragments to add.
+ * @off: The offset into @walk to add frags from, also used with @st and
+ * @copy_len.
+ * @len: The length of data to add covering frags from @walk into @skb.
+ * This must be <= @skblen.
+ * @st: The sequence state to copy from into the new head skb.
+ * @copy_len: Copy @copy_len bytes from @st at offset @off into the new skb
+ * linear space.
+ *
+ * Create a new sk_buff `skb` using the template @tpl. Copy @copy_len bytes from
+ * @st into the new skb linear space, and then add shared fragments from the
+ * frag walk for the remaining @len of data (i.e., @len - @copy_len bytes).
+ *
+ * Return: The newly allocated sk_buff `skb` or NULL if an error occurs.
+ */
+struct sk_buff *iptfs_pskb_add_frags(struct sk_buff *tpl,
+ struct skb_frag_walk *walk, u32 off,
+ u32 len, struct skb_seq_state *st,
+ u32 copy_len)
+{
+ struct sk_buff *skb;
+
+ skb = iptfs_alloc_skb(tpl, copy_len, false);
+ if (!skb)
+ return NULL;
+
+ /* this should not normally be happening */
+ if (!skb_can_add_frags(skb, walk, off + copy_len, len - copy_len)) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ if (copy_len &&
+ skb_copy_bits_seq(st, off, skb_put(skb, copy_len), copy_len)) {
+ XFRM_INC_STATS(dev_net(st->root_skb->dev),
+ LINUX_MIB_XFRMINERROR);
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ skb_add_frags(skb, walk, off + copy_len, len - copy_len);
+ return skb;
+}
+
+/**
+ * iptfs_pskb_extract_seq() - Create and load data into a new sk_buff.
+ * @skblen: the total data size for `skb`.
+ * @st: The source for the rest of the data to copy into `skb`.
+ * @off: The offset into @st to copy data from.
+ * @len: The length of data to copy from @st into `skb`. This must be <=
+ * @skblen.
+ *
+ * Create a new sk_buff `skb` with @skblen of packet data space. If non-zero,
+ * copy @rlen bytes of @runt into `skb`. Then using seq functions copy @len
+ * bytes from @st into `skb` starting from @off.
+ *
+ * It is an error for @len to be greater than the amount of data left in @st.
+ *
+ * Return: The newly allocated sk_buff `skb` or NULL if an error occurs.
+ */
+static struct sk_buff *
+iptfs_pskb_extract_seq(u32 skblen, struct skb_seq_state *st, u32 off, int len)
+{
+ struct sk_buff *skb = iptfs_alloc_skb(st->root_skb, skblen, false);
+
+ if (!skb)
+ return NULL;
+ if (skb_copy_bits_seq(st, off, skb_put(skb, len), len)) {
+ XFRM_INC_STATS(dev_net(st->root_skb->dev),
+ LINUX_MIB_XFRMINERROR);
+ kfree_skb(skb);
+ return NULL;
+ }
+ return skb;
+}
+
+/**
+ * iptfs_input_save_runt() - save data in xtfs runt space.
+ *
+ * Save the small (`len`) start of a fragmented packet in `buf` in the xtfs data
+ * runt space.
+ */
+static void iptfs_input_save_runt(struct xfrm_iptfs_data *xtfs, u64 seq,
+ u8 *buf, int len)
+{
+ BUG_ON(xtfs->ra_newskb); /* we won't have a new SKB yet */
+
+ memcpy(xtfs->ra_runt, buf, len);
+
+ xtfs->ra_runtlen = len;
+ xtfs->ra_wantseq = seq + 1;
+}
+
+/**
+ * __iptfs_iphlen() - return the v4/v6 header length using packet data.
+ *
+ * The version data is expected to be valid (i.e., either 4 or 6).
+ */
+static u32 __iptfs_iphlen(u8 *data)
+{
+ struct iphdr *iph = (struct iphdr *)data;
+
+ if (iph->version == 0x4)
+ return sizeof(*iph);
+ BUG_ON(iph->version != 0x6);
+ return sizeof(struct ipv6hdr);
+}
+
+/**
+ * __iptfs_iplen() - return the v4/v6 length using packet data.
+ *
+ * Grab the IPv4 or IPv6 length value in the start of the inner packet header
+ * pointed to by `data`. Assumes data len is enough for the length field only.
+ *
+ * The version data is expected to be valid (i.e., either 4 or 6).
+ */
+static u32 __iptfs_iplen(u8 *data)
+{
+ struct iphdr *iph = (struct iphdr *)data;
+
+ if (iph->version == 0x4)
+ return ntohs(iph->tot_len);
+ BUG_ON(iph->version != 0x6);
+ return ntohs(((struct ipv6hdr *)iph)->payload_len) +
+ sizeof(struct ipv6hdr);
+}
+
+/**
+ * iptfs_complete_inner_skb() - finish preparing the inner packet for gro recv.
+ *
+ * Finish the standard xfrm processing on the inner packet prior to sending back
+ * through gro_cells_receive. We do this separately b/c we are building a list
+ * of packets in the hopes that one day a list will be taken by
+ * xfrm_input.
+ */
+static void iptfs_complete_inner_skb(struct xfrm_state *x, struct sk_buff *skb)
+{
+ skb_reset_network_header(skb);
+
+ /* The packet is going back through gro_cells_receive no need to
+ * set this.
+ */
+ skb_reset_transport_header(skb);
+
+ /* Packet already has checksum value set. */
+ skb->ip_summed = CHECKSUM_NONE;
+
+ /* Our skb will contain the header data copied when this outer packet
+ * which contained the start of this inner packet. This is true
+ * when we allocate a new skb as well as when we reuse the existing skb.
+ */
+ if (ip_hdr(skb)->version == 0x4) {
+ struct iphdr *iph = ip_hdr(skb);
+
+ if (x->props.flags & XFRM_STATE_DECAP_DSCP)
+ ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, iph);
+ if (!(x->props.flags & XFRM_STATE_NOECN))
+ if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
+ IP_ECN_set_ce(iph);
+
+ skb->protocol = htons(ETH_P_IP);
+ } else {
+ struct ipv6hdr *iph = ipv6_hdr(skb);
+
+ if (x->props.flags & XFRM_STATE_DECAP_DSCP)
+ ipv6_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, iph);
+ if (!(x->props.flags & XFRM_STATE_NOECN))
+ if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
+ IP6_ECN_set_ce(skb, iph);
+
+ skb->protocol = htons(ETH_P_IPV6);
+ }
+}
+
+static void __iptfs_reassem_done(struct xfrm_iptfs_data *xtfs, bool free)
+{
+ int ret;
+
+ assert_spin_locked(&xtfs->drop_lock);
+
+ /* We don't care if it works locking takes care of things */
+ ret = hrtimer_try_to_cancel(&xtfs->drop_timer);
+ if (free)
+ kfree_skb(xtfs->ra_newskb);
+ xtfs->ra_newskb = NULL;
+}
+
+/**
+ * iptfs_reassem_done() - In-progress packet is aborted free the state.
+ */
+static void iptfs_reassem_abort(struct xfrm_iptfs_data *xtfs)
+{
+ __iptfs_reassem_done(xtfs, true);
+}
+
+/**
+ * iptfs_reassem_done() - In-progress packet is complete, clear the state.
+ */
+static void iptfs_reassem_done(struct xfrm_iptfs_data *xtfs)
+{
+ __iptfs_reassem_done(xtfs, false);
+}
+
+/**
+ * iptfs_reassem_cont() - Continue the reassembly of an inner packets.
+ *
+ * Process an IPTFS payload that has a non-zero `blkoff` or when we are
+ * expecting the continuation b/c we have a runt or in-progress packet.
+ */
+static u32 iptfs_reassem_cont(struct xfrm_iptfs_data *xtfs, u64 seq,
+ struct skb_seq_state *st, struct sk_buff *skb,
+ u32 data, u32 blkoff, struct list_head *list)
+{
+ struct skb_frag_walk _fragwalk;
+ struct skb_frag_walk *fragwalk = NULL;
+ struct sk_buff *newskb = xtfs->ra_newskb;
+ u32 remaining = skb->len - data;
+ u32 runtlen = xtfs->ra_runtlen;
+ u32 copylen, fraglen, ipremain, iphlen, iphremain, rrem;
+
+ /* Handle packet fragment we aren't expecting */
+ if (!runtlen && !xtfs->ra_newskb)
+ return data + min(blkoff, remaining);
+
+ /* Important to remember that input to this function is an ordered
+ * packet stream (unless the user disabled the reorder window). Thus if
+ * we are waiting for, and expecting the next packet so we can continue
+ * assembly, a newer sequence number indicates older ones are not coming
+ * (or if they do should be ignored). Technically we can receive older
+ * ones when the reorder window is disabled; however, the user should
+ * have disabled fragmentation in this case, and regardless we don't
+ * deal with it.
+ *
+ * blkoff could be zero if the stream is messed up (or it's an all pad
+ * insertion) be careful to handle that case in each of the below
+ */
+
+ /* Too old case: This can happen when the reorder window is disabled so
+ * ordering isn't actually guaranteed.
+ */
+ if (seq < xtfs->ra_wantseq)
+ return data + remaining;
+
+ /* Too new case: We missed what we wanted cleanup. */
+ if (seq > xtfs->ra_wantseq) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINIPTFSERROR);
+ goto abandon;
+ }
+
+ if (blkoff == 0) {
+ if ((*skb->data & 0xF0) != 0) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINIPTFSERROR);
+ goto abandon;
+ }
+ /* Handle all pad case, advance expected sequence number.
+ * (RFC 9347 S2.2.3)
+ */
+ xtfs->ra_wantseq++;
+ /* will end parsing */
+ return data + remaining;
+ }
+
+ if (runtlen) {
+ BUG_ON(xtfs->ra_newskb);
+
+ /* Regardless of what happens we're done with the runt */
+ xtfs->ra_runtlen = 0;
+
+ /* The start of this inner packet was at the very end of the last
+ * iptfs payload which didn't include enough for the ip header
+ * length field. We must have *at least* that now.
+ */
+ rrem = sizeof(xtfs->ra_runt) - runtlen;
+ if (remaining < rrem || blkoff < rrem) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINIPTFSERROR);
+ goto abandon;
+ }
+
+ /* fill in the runt data */
+ if (skb_copy_bits_seq(st, data, &xtfs->ra_runt[runtlen],
+ rrem)) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINBUFFERERROR);
+ goto abandon;
+ }
+
+ /* We have enough data to get the ip length value now,
+ * allocate an in progress skb
+ */
+ ipremain = __iptfs_iplen(xtfs->ra_runt);
+ if (ipremain < sizeof(xtfs->ra_runt)) {
+ /* length has to be at least runtsize large */
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINIPTFSERROR);
+ goto abandon;
+ }
+
+ /* For the runt case we don't attempt sharing currently. NOTE:
+ * Currently, this IPTFS implementation will not create runts.
+ */
+
+ newskb = iptfs_alloc_skb(skb, ipremain, false);
+ if (!newskb) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINERROR);
+ goto abandon;
+ }
+ xtfs->ra_newskb = newskb;
+
+ /* Copy the runt data into the buffer, but leave data
+ * pointers the same as normal non-runt case. The extra `rrem`
+ * recopied bytes are basically cacheline free. Allows using
+ * same logic below to complete.
+ */
+ memcpy(skb_put(newskb, runtlen), xtfs->ra_runt,
+ sizeof(xtfs->ra_runt));
+ }
+
+ /* Continue reassembling the packet */
+ ipremain = __iptfs_iplen(newskb->data);
+ iphlen = __iptfs_iphlen(newskb->data);
+
+ /* Sanity check, we created the newskb knowing the IP length so the IP
+ * length can't now be shorter.
+ */
+ BUG_ON(newskb->len > ipremain);
+
+ ipremain -= newskb->len;
+ if (blkoff < ipremain) {
+ /* Corrupt data, we don't have enough to complete the packet */
+ XFRM_INC_STATS(dev_net(skb->dev), LINUX_MIB_XFRMINIPTFSERROR);
+ goto abandon;
+ }
+
+ /* We want the IP header in linear space */
+ if (newskb->len < iphlen) {
+ iphremain = iphlen - newskb->len;
+ if (blkoff < iphremain) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINIPTFSERROR);
+ goto abandon;
+ }
+ fraglen = min(blkoff, remaining);
+ copylen = min(fraglen, iphremain);
+ BUG_ON(skb_tailroom(newskb) < copylen);
+ if (skb_copy_bits_seq(st, data, skb_put(newskb, copylen), copylen)) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINBUFFERERROR);
+ goto abandon;
+ }
+ /* this is a silly condition that might occur anyway */
+ if (copylen < iphremain) {
+ xtfs->ra_wantseq++;
+ return data + fraglen;
+ }
+ /* update data and things derived from it */
+ data += copylen;
+ blkoff -= copylen;
+ remaining -= copylen;
+ ipremain -= copylen;
+ }
+
+ fraglen = min(blkoff, remaining);
+ copylen = min(fraglen, ipremain);
+
+ /* If we may have the opportunity to share prepare a fragwalk. */
+ if (!skb_has_frag_list(skb) && !skb_has_frag_list(newskb) &&
+ (skb->head_frag || skb->len == skb->data_len) &&
+ skb->pp_recycle == newskb->pp_recycle) {
+ fragwalk = &_fragwalk;
+ skb_prepare_frag_walk(skb, data, fragwalk);
+ }
+
+ /* Try share then copy. */
+ if (fragwalk && skb_can_add_frags(newskb, fragwalk, data, copylen)) {
+ u32 leftover;
+
+ leftover = skb_add_frags(newskb, fragwalk, data, copylen);
+ BUG_ON(leftover != 0);
+ } else {
+ /* We verified this was true in the main receive routine */
+ BUG_ON(skb_tailroom(newskb) < copylen);
+
+ /* copy fragment data into newskb */
+ if (skb_copy_bits_seq(st, data, skb_put(newskb, copylen), copylen)) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINBUFFERERROR);
+ goto abandon;
+ }
+ }
+
+ if (copylen < ipremain) {
+ xtfs->ra_wantseq++;
+ } else {
+ /* We are done with packet reassembly! */
+ BUG_ON(copylen != ipremain);
+ iptfs_reassem_done(xtfs);
+ iptfs_complete_inner_skb(xtfs->x, newskb);
+ list_add_tail(&newskb->list, list);
+ }
+
+ /* will continue on to new data block or end */
+ return data + fraglen;
+
+abandon:
+ if (xtfs->ra_newskb) {
+ iptfs_reassem_abort(xtfs);
+ } else {
+ xtfs->ra_runtlen = 0;
+ xtfs->ra_wantseq = 0;
+ }
+ /* skip past fragment, maybe to end */
+ return data + min(blkoff, remaining);
+}
+
+/**
+ * iptfs_input_ordered() - handle next in order IPTFS payload.
+ *
+ * Process the IPTFS payload in `skb` and consume it afterwards.
+ */
+static int iptfs_input_ordered(struct xfrm_state *x, struct sk_buff *skb)
+{
+ u8 hbytes[sizeof(struct ipv6hdr)];
+ struct ip_iptfs_cc_hdr iptcch;
+ struct skb_seq_state skbseq;
+ struct skb_frag_walk _fragwalk;
+ struct skb_frag_walk *fragwalk = NULL;
+ struct list_head sublist; /* rename this it's just a list */
+ struct sk_buff *first_skb, *defer, *next;
+ const unsigned char *old_mac;
+ struct xfrm_iptfs_data *xtfs;
+ struct ip_iptfs_hdr *ipth;
+ struct iphdr *iph;
+ struct net *net;
+ u32 remaining, first_iplen, iplen, iphlen, data, tail;
+ u32 blkoff, capturelen;
+ u64 seq;
+
+ xtfs = x->mode_data;
+ net = dev_net(skb->dev);
+ first_skb = NULL;
+ defer = NULL;
+
+ seq = __esp_seq(skb);
+
+ /* Large enough to hold both types of header */
+ ipth = (struct ip_iptfs_hdr *)&iptcch;
+
+ /* Save the old mac header if set */
+ old_mac = skb_mac_header_was_set(skb) ? skb_mac_header(skb) : NULL;
+
+ skb_prepare_seq_read(skb, 0, skb->len, &skbseq);
+
+ /* Get the IPTFS header and validate it */
+
+ if (skb_copy_bits_seq(&skbseq, 0, ipth, sizeof(*ipth))) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
+ goto done;
+ }
+ data = sizeof(*ipth);
+
+ trace_iptfs_egress_recv(skb, xtfs, htons(ipth->block_offset));
+
+ /* Set data past the basic header */
+ if (ipth->subtype == IPTFS_SUBTYPE_CC) {
+ /* Copy the rest of the CC header */
+ remaining = sizeof(iptcch) - sizeof(*ipth);
+ if (skb_copy_bits_seq(&skbseq, data, ipth + 1, remaining)) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
+ goto done;
+ }
+ data += remaining;
+ } else if (ipth->subtype != IPTFS_SUBTYPE_BASIC) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
+ goto done;
+ }
+
+ if (ipth->flags != 0) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
+ goto done;
+ }
+
+ INIT_LIST_HEAD(&sublist);
+
+ /* Handle fragment at start of payload, and/or waiting reassembly. */
+
+ blkoff = ntohs(ipth->block_offset);
+ /* check before locking i.e., maybe */
+ if (blkoff || xtfs->ra_runtlen || xtfs->ra_newskb) {
+ spin_lock(&xtfs->drop_lock);
+
+ /* check again after lock */
+ if (blkoff || xtfs->ra_runtlen || xtfs->ra_newskb) {
+ data = iptfs_reassem_cont(xtfs, seq, &skbseq, skb, data,
+ blkoff, &sublist);
+ }
+
+ spin_unlock(&xtfs->drop_lock);
+ }
+
+ /* New packets */
+
+ tail = skb->len;
+ BUG_ON(xtfs->ra_newskb && data < tail);
+
+ while (data < tail) {
+ u32 protocol = 0;
+
+ /* Gather information on the next data block.
+ * `data` points to the start of the data block.
+ */
+ remaining = tail - data;
+
+ /* try and copy enough bytes to read length from ipv4/ipv6 */
+ iphlen = min_t(u32, remaining, 6);
+ if (skb_copy_bits_seq(&skbseq, data, hbytes, iphlen)) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
+ goto done;
+ }
+
+ iph = (struct iphdr *)hbytes;
+ if (iph->version == 0x4) {
+ /* must have at least tot_len field present */
+ if (remaining < 4) {
+ /* save the bytes we have, advance data and exit */
+ iptfs_input_save_runt(xtfs, seq, hbytes,
+ remaining);
+ data += remaining;
+ break;
+ }
+
+ iplen = htons(iph->tot_len);
+ iphlen = iph->ihl << 2;
+ protocol = htons(ETH_P_IP);
+ XFRM_MODE_SKB_CB(skbseq.root_skb)->tos = iph->tos;
+ } else if (iph->version == 0x6) {
+ /* must have at least payload_len field present */
+ if (remaining < 6) {
+ /* save the bytes we have, advance data and exit */
+ iptfs_input_save_runt(xtfs, seq, hbytes,
+ remaining);
+ data += remaining;
+ break;
+ }
+
+ iplen = htons(((struct ipv6hdr *)hbytes)->payload_len);
+ iplen += sizeof(struct ipv6hdr);
+ iphlen = sizeof(struct ipv6hdr);
+ protocol = htons(ETH_P_IPV6);
+ XFRM_MODE_SKB_CB(skbseq.root_skb)->tos =
+ ipv6_get_dsfield((struct ipv6hdr *)iph);
+ } else if (iph->version == 0x0) {
+ /* pad */
+ data = tail;
+ break;
+ } else {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
+ goto done;
+ }
+
+ if (unlikely(skbseq.stepped_offset)) {
+ /* We need to reset our seq read, it can't backup at
+ * this point.
+ */
+ struct sk_buff *save = skbseq.root_skb;
+
+ skb_abort_seq_read(&skbseq);
+ skb_prepare_seq_read(save, data, tail, &skbseq);
+ }
+
+ if (first_skb) {
+ skb = NULL;
+ } else {
+ first_skb = skb;
+ first_iplen = iplen;
+ fragwalk = NULL;
+
+ /* We are going to skip over `data` bytes to reach the
+ * start of the IP header of `iphlen` len for `iplen`
+ * inner packet.
+ */
+
+ if (skb_has_frag_list(skb)) {
+ defer = skb;
+ skb = NULL;
+ } else if (data + iphlen <= skb_headlen(skb) &&
+ /* make sure our header is 32-bit aligned? */
+ /* ((uintptr_t)(skb->data + data) & 0x3) == 0 && */
+ skb_tailroom(skb) + tail - data >= iplen) {
+ /* Reuse the received skb.
+ *
+ * We have enough headlen to pull past any
+ * initial fragment data, leaving at least the
+ * IP header in the linear buffer space.
+ *
+ * For linear buffer space we only require that
+ * linear buffer space is large enough to
+ * eventually hold the entire reassembled
+ * packet (by including tailroom in the check).
+ *
+ * For non-linear tailroom is 0 and so we only
+ * re-use if the entire packet is present
+ * already.
+ *
+ * NOTE: there are many more options for
+ * sharing, KISS for now. Also, this can produce
+ * skb's with the IP header unaligned to 32
+ * bits. If that ends up being a problem then a
+ * check should be added to the conditional
+ * above that the header lies on a 32-bit
+ * boundary as well.
+ */
+ skb_pull(skb, data);
+
+ /* our range just changed */
+ data = 0;
+ tail = skb->len;
+ remaining = skb->len;
+
+ skb->protocol = protocol;
+ skb_mac_header_rebuild(skb);
+ if (skb->mac_len)
+ eth_hdr(skb)->h_proto = skb->protocol;
+
+ /* all pointers could be changed now reset walk */
+ skb_abort_seq_read(&skbseq);
+ skb_prepare_seq_read(skb, data, tail, &skbseq);
+ } else if (skb->head_frag &&
+ /* We have the IP header right now */
+ remaining >= iphlen) {
+ fragwalk = &_fragwalk;
+ skb_prepare_frag_walk(skb, data, fragwalk);
+ defer = skb;
+ skb = NULL;
+ } else {
+ /* We couldn't reuse the input skb so allocate a
+ * new one.
+ */
+ defer = skb;
+ skb = NULL;
+ }
+
+ /* Don't trim `first_skb` until the end as we are
+ * walking that data now.
+ */
+ }
+
+ capturelen = min(iplen, remaining);
+ if (!skb) {
+ if (!fragwalk ||
+ /* Large enough to be worth sharing */
+ iplen < IPTFS_PKT_SHARE_MIN ||
+ /* Have IP header + some data to share. */
+ capturelen <= iphlen ||
+ /* Try creating skb and adding frags */
+ !(skb = iptfs_pskb_add_frags(first_skb, fragwalk,
+ data, capturelen,
+ &skbseq, iphlen))) {
+ skb = iptfs_pskb_extract_seq(iplen, &skbseq,
+ data, capturelen);
+ }
+ if (!skb) {
+ /* skip to next packet or done */
+ data += capturelen;
+ continue;
+ }
+ BUG_ON(skb->len != capturelen);
+
+ skb->protocol = protocol;
+ if (old_mac) {
+ /* rebuild the mac header */
+ skb_set_mac_header(skb, -first_skb->mac_len);
+ memcpy(skb_mac_header(skb), old_mac,
+ first_skb->mac_len);
+ eth_hdr(skb)->h_proto = skb->protocol;
+ }
+ }
+
+ data += capturelen;
+
+ if (skb->len < iplen) {
+ BUG_ON(data != tail);
+ BUG_ON(xtfs->ra_newskb);
+
+ /* Start reassembly */
+ spin_lock(&xtfs->drop_lock);
+
+ xtfs->ra_newskb = skb;
+ xtfs->ra_wantseq = seq + 1;
+ if (!hrtimer_is_queued(&xtfs->drop_timer)) {
+ /* softirq blocked lest the timer fire and interrupt us */
+ BUG_ON(!in_interrupt());
+ hrtimer_start(&xtfs->drop_timer,
+ xtfs->drop_time_ns,
+ IPTFS_HRTIMER_MODE);
+ }
+
+ spin_unlock(&xtfs->drop_lock);
+
+ break;
+ }
+
+ iptfs_complete_inner_skb(x, skb);
+ list_add_tail(&skb->list, &sublist);
+ }
+
+ if (data != tail)
+ /* this should not happen from the above code */
+ XFRM_INC_STATS(dev_net(skb->dev), LINUX_MIB_XFRMINIPTFSERROR);
+
+ if (first_skb && first_iplen && !defer && first_skb != xtfs->ra_newskb) {
+ /* first_skb is queued b/c !defer and not partial */
+ if (pskb_trim(first_skb, first_iplen)) {
+ /* error trimming */
+ list_del(&first_skb->list);
+ defer = first_skb;
+ }
+ first_skb->ip_summed = CHECKSUM_NONE;
+ }
+
+ /* Send the packets! */
+ list_for_each_entry_safe(skb, next, &sublist, list) {
+ BUG_ON(skb == defer);
+ skb_list_del_init(skb);
+ if (xfrm_input(skb, 0, 0, -3))
+ kfree_skb(skb);
+ }
+
+done:
+ skb = skbseq.root_skb;
+ skb_abort_seq_read(&skbseq);
+
+ if (defer) {
+ consume_skb(defer);
+ } else if (!first_skb) {
+ /* skb is the original passed in skb, but we didn't get far
+ * enough to process it as the first_skb, if we had it would
+ * either be save in ra_newskb, trimmed and sent on as an skb or
+ * placed in defer to be freed.
+ */
+ BUG_ON(!skb);
+ kfree_skb(skb);
+ }
+
+ return 0;
+}
+
+/* ------------------------------- */
+/* Input (Egress) Re-ordering Code */
+/* ------------------------------- */
+
+static void __vec_shift(struct xfrm_iptfs_data *xtfs, u32 shift)
+{
+ u32 savedlen = xtfs->w_savedlen;
+
+ if (shift > savedlen)
+ shift = savedlen;
+ if (shift != savedlen)
+ memcpy(xtfs->w_saved, xtfs->w_saved + shift,
+ (savedlen - shift) * sizeof(*xtfs->w_saved));
+ memset(xtfs->w_saved + savedlen - shift, 0,
+ shift * sizeof(*xtfs->w_saved));
+ xtfs->w_savedlen -= shift;
+}
+
+static int __reorder_past(struct xfrm_iptfs_data *xtfs, struct sk_buff *inskb,
+ struct list_head *freelist, u32 *fcount)
+{
+ list_add_tail(&inskb->list, freelist);
+ (*fcount)++;
+ return 0;
+}
+
+static u32 __reorder_drop(struct xfrm_iptfs_data *xtfs, struct list_head *list)
+
+{
+ struct skb_wseq *s, *se;
+ const u32 savedlen = xtfs->w_savedlen;
+ u64 wantseq = xtfs->w_wantseq;
+ time64_t now = ktime_get_raw_fast_ns();
+ u32 count = 0;
+ u32 scount = 0;
+
+ BUG_ON(!savedlen);
+ if (xtfs->w_saved[0].drop_time > now)
+ goto set_timer;
+
+ wantseq = ++xtfs->w_wantseq;
+
+ /* Keep flushing packets until we reach a drop time greater than now. */
+ s = xtfs->w_saved;
+ se = s + savedlen;
+ do {
+ /* Walking past empty slots until we reach a packet */
+ for (; s < se && !s->skb; s++)
+ if (s->drop_time > now)
+ goto outerdone;
+ /* Sending packets until we hit another empty slot. */
+ for (; s < se && s->skb; scount++, s++)
+ list_add_tail(&s->skb->list, list);
+ } while (s < se);
+outerdone:
+
+ count = s - xtfs->w_saved;
+ if (count) {
+ xtfs->w_wantseq += count;
+
+ /* Shift handled slots plus final empty slot into slot 0. */
+ __vec_shift(xtfs, count);
+ }
+
+ if (xtfs->w_savedlen) {
+set_timer:
+ /* Drifting is OK */
+ hrtimer_start(&xtfs->drop_timer,
+ xtfs->w_saved[0].drop_time - now,
+ IPTFS_HRTIMER_MODE);
+ }
+ return scount;
+}
+
+static u32 __reorder_this(struct xfrm_iptfs_data *xtfs, struct sk_buff *inskb,
+ struct list_head *list)
+
+{
+ struct skb_wseq *s, *se;
+ const u32 savedlen = xtfs->w_savedlen;
+ u64 wantseq = xtfs->w_wantseq;
+ u32 count = 0;
+
+ /* Got what we wanted. */
+ list_add_tail(&inskb->list, list);
+ wantseq = ++xtfs->w_wantseq;
+ if (!savedlen)
+ return 1;
+
+ /* Flush remaining consecutive packets. */
+
+ /* Keep sending until we hit another missed pkt. */
+ for (s = xtfs->w_saved, se = s + savedlen; s < se && s->skb; s++)
+ list_add_tail(&s->skb->list, list);
+ count = s - xtfs->w_saved;
+ if (count)
+ xtfs->w_wantseq += count;
+
+ /* Shift handled slots plus final empty slot into slot 0. */
+ __vec_shift(xtfs, count + 1);
+
+ return count + 1;
+}
+
+/* Set the slot's drop time and all the empty slots below it until reaching a
+ * filled slot which will already be set.
+ */
+static void iptfs_set_window_drop_times(struct xfrm_iptfs_data *xtfs, int index)
+{
+ const u32 savedlen = xtfs->w_savedlen;
+ struct skb_wseq *s = xtfs->w_saved;
+ time64_t drop_time;
+
+ assert_spin_locked(&xtfs->drop_lock);
+
+ if (savedlen > index + 1) {
+ /* we are below another, our drop time and the timer are already set */
+ BUG_ON(xtfs->w_saved[index + 1].drop_time !=
+ xtfs->w_saved[index].drop_time);
+ return;
+ }
+ /* we are the most future so get a new drop time. */
+ drop_time = ktime_get_raw_fast_ns();
+ drop_time += xtfs->drop_time_ns;
+
+ /* Walk back through the array setting drop times as we go */
+ s[index].drop_time = drop_time;
+ while (index-- > 0 && !s[index].skb)
+ s[index].drop_time = drop_time;
+
+ /* If we walked all the way back, schedule the drop timer if needed */
+ if (index == -1 && !hrtimer_is_queued(&xtfs->drop_timer))
+ hrtimer_start(&xtfs->drop_timer, xtfs->drop_time_ns,
+ IPTFS_HRTIMER_MODE);
+}
+
+static u32 __reorder_future_fits(struct xfrm_iptfs_data *xtfs,
+ struct sk_buff *inskb,
+ struct list_head *freelist, u32 *fcount)
+{
+ const u32 nslots = xtfs->cfg.reorder_win_size + 1;
+ const u64 inseq = __esp_seq(inskb);
+ const u64 wantseq = xtfs->w_wantseq;
+ const u64 distance = inseq - wantseq;
+ const u32 savedlen = xtfs->w_savedlen;
+ const u32 index = distance - 1;
+
+ BUG_ON(distance >= nslots);
+
+ /* Handle future sequence number received which fits in the window.
+ *
+ * We know we don't have the seq we want so we won't be able to flush
+ * anything.
+ */
+
+ /* slot count is 4, saved size is 3 savedlen is 2
+ *
+ * "window boundary" is based on the fixed window size
+ * distance is also slot number
+ * index is an array index (i.e., - 1 of slot)
+ * : : - implicit NULL after array len
+ *
+ * +--------- used length (savedlen == 2)
+ * | +----- array size (nslots - 1 == 3)
+ * | | + window boundary (nslots == 4)
+ * V V | V
+ * |
+ * 0 1 2 3 | slot number
+ * --- 0 1 2 | array index
+ * [-] [b] : :| array
+ *
+ * "2" "3" "4" *5*| seq numbers
+ *
+ * We receive seq number 5
+ * distance == 3 [inseq(5) - w_wantseq(2)]
+ * index == 2 [distance(6) - 1]
+ */
+
+ if (xtfs->w_saved[index].skb) {
+ /* a dup of a future */
+ list_add_tail(&inskb->list, freelist);
+ (*fcount)++;
+ return 0;
+ }
+
+ xtfs->w_saved[index].skb = inskb;
+ xtfs->w_savedlen = max(savedlen, index + 1);
+ iptfs_set_window_drop_times(xtfs, index);
+
+ return 0;
+}
+
+static u32 __reorder_future_shifts(struct xfrm_iptfs_data *xtfs,
+ struct sk_buff *inskb,
+ struct list_head *list,
+ struct list_head *freelist, u32 *fcount)
+{
+ const u32 nslots = xtfs->cfg.reorder_win_size + 1;
+ const u64 inseq = __esp_seq(inskb);
+ u32 savedlen = xtfs->w_savedlen;
+ u64 wantseq = xtfs->w_wantseq;
+ struct sk_buff *slot0 = NULL;
+ u64 last_drop_seq = xtfs->w_wantseq;
+ u64 distance, extra_drops, missed, s0seq;
+ u32 count = 0;
+ struct skb_wseq *wnext;
+ u32 beyond, shifting, slot;
+
+ BUG_ON(inseq <= wantseq);
+ distance = inseq - wantseq;
+ BUG_ON(distance <= nslots - 1);
+ beyond = distance - (nslots - 1);
+ missed = 0;
+
+ /* Handle future sequence number received.
+ *
+ * IMPORTANT: we are at least advancing w_wantseq (i.e., wantseq) by 1
+ * b/c we are beyond the window boundary.
+ *
+ * We know we don't have the wantseq so that counts as a drop.
+ */
+
+ /* ex: slot count is 4, array size is 3 savedlen is 2, slot 0 is the
+ * missing sequence number.
+ *
+ * the final slot at savedlen (index savedlen - 1) is always occupied.
+ *
+ * beyond is "beyond array size" not savedlen.
+ *
+ * +--------- array length (savedlen == 2)
+ * | +----- array size (nslots - 1 == 3)
+ * | | +- window boundary (nslots == 4)
+ * V V | V
+ * |
+ * 0 1 2 3 | slot number
+ * --- 0 1 2 | array index
+ * [b] [c] : :| array
+ * |
+ * "2" "3" "4" "5"|*6* seq numbers
+ *
+ * We receive seq number 6
+ * distance == 4 [inseq(6) - w_wantseq(2)]
+ * newslot == distance
+ * index == 3 [distance(4) - 1]
+ * beyond == 1 [newslot(4) - lastslot((nslots(4) - 1))]
+ * shifting == 1 [min(savedlen(2), beyond(1)]
+ * slot0_skb == [b], and should match w_wantseq
+ *
+ * +--- window boundary (nslots == 4)
+ * 0 1 2 3 | 4 slot number
+ * --- 0 1 2 | 3 array index
+ * [b] : : : :| array
+ * "2" "3" "4" "5" *6* seq numbers
+ *
+ * We receive seq number 6
+ * distance == 4 [inseq(6) - w_wantseq(2)]
+ * newslot == distance
+ * index == 3 [distance(4) - 1]
+ * beyond == 1 [newslot(4) - lastslot((nslots(4) - 1))]
+ * shifting == 1 [min(savedlen(1), beyond(1)]
+ * slot0_skb == [b] and should match w_wantseq
+ *
+ * +-- window boundary (nslots == 4)
+ * 0 1 2 3 | 4 5 6 slot number
+ * --- 0 1 2 | 3 4 5 array index
+ * [-] [c] : :| array
+ * "2" "3" "4" "5" "6" "7" *8* seq numbers
+ *
+ * savedlen = 2, beyond = 3
+ * iter 1: slot0 == NULL, missed++, lastdrop = 2 (2+1-1), slot0 = [-]
+ * iter 2: slot0 == NULL, missed++, lastdrop = 3 (2+2-1), slot0 = [c]
+ * 2 < 3, extra = 1 (3-2), missed += extra, lastdrop = 4 (2+2+1-1)
+ *
+ * We receive seq number 8
+ * distance == 6 [inseq(8) - w_wantseq(2)]
+ * newslot == distance
+ * index == 5 [distance(6) - 1]
+ * beyond == 3 [newslot(6) - lastslot((nslots(4) - 1))]
+ * shifting == 2 [min(savedlen(2), beyond(3)]
+ *
+ * slot0_skb == NULL changed from [b] when "savedlen < beyond" is true.
+ */
+
+ /* Now send any packets that are being shifted out of saved, and account
+ * for missing packets that are exiting the window as we shift it.
+ */
+
+ /* If savedlen > beyond we are shifting some, else all. */
+ shifting = min(savedlen, beyond);
+
+ /* slot0 is the buf that just shifted out and into slot0 */
+ slot0 = NULL;
+ s0seq = wantseq;
+ last_drop_seq = s0seq;
+ wnext = xtfs->w_saved;
+ for (slot = 1; slot <= shifting; slot++, wnext++) {
+ /* handle what was in slot0 before we occupy it */
+ if (!slot0) {
+ last_drop_seq = s0seq;
+ missed++;
+ } else {
+ list_add_tail(&slot0->list, list);
+ count++;
+ }
+ s0seq++;
+ slot0 = wnext->skb;
+ wnext->skb = NULL;
+ }
+
+ /* slot0 is now either NULL (in which case it's what we now are waiting
+ * for, or a buf in which case we need to handle it like we received it;
+ * however, we may be advancing past that buffer as well..
+ */
+
+ /* Handle case where we need to shift more than we had saved, slot0 will
+ * be NULL iff savedlen is 0, otherwise slot0 will always be
+ * non-NULL b/c we shifted the final element, which is always set if
+ * there is any saved, into slot0.
+ */
+ if (savedlen < beyond) {
+ extra_drops = beyond - savedlen;
+ if (savedlen == 0) {
+ BUG_ON(slot0);
+ s0seq += extra_drops;
+ last_drop_seq = s0seq - 1;
+ } else {
+ extra_drops--; /* we aren't dropping what's in slot0 */
+ BUG_ON(!slot0);
+ list_add_tail(&slot0->list, list);
+ /* if extra_drops then we are going past this slot0
+ * so we can safely advance last_drop_seq
+ */
+ if (extra_drops)
+ last_drop_seq = s0seq + extra_drops;
+ s0seq += extra_drops + 1;
+ count++;
+ }
+ missed += extra_drops;
+ slot0 = NULL;
+ /* slot0 has had an empty slot pushed into it */
+ }
+
+ /* Remove the entries */
+ __vec_shift(xtfs, beyond);
+
+ /* Advance want seq */
+ xtfs->w_wantseq += beyond;
+
+ /* Process drops here when implementing congestion control */
+
+ /* We've shifted. plug the packet in at the end. */
+ xtfs->w_savedlen = nslots - 1;
+ xtfs->w_saved[xtfs->w_savedlen - 1].skb = inskb;
+ iptfs_set_window_drop_times(xtfs, xtfs->w_savedlen - 1);
+
+ /* if we don't have a slot0 then we must wait for it */
+ if (!slot0)
+ return count;
+
+ /* If slot0, seq must match new want seq */
+ BUG_ON(xtfs->w_wantseq != __esp_seq(slot0));
+
+ /* slot0 is valid, treat like we received expected. */
+ count += __reorder_this(xtfs, slot0, list);
+ return count;
+}
+
+/* Receive a new packet into the reorder window. Return a list of ordered
+ * packets from the window.
+ */
+static u32 iptfs_input_reorder(struct xfrm_iptfs_data *xtfs,
+ struct sk_buff *inskb, struct list_head *list,
+ struct list_head *freelist, u32 *fcount)
+{
+ const u32 nslots = xtfs->cfg.reorder_win_size + 1;
+ u64 inseq = __esp_seq(inskb);
+ u64 wantseq;
+
+ assert_spin_locked(&xtfs->drop_lock);
+
+ if (unlikely(!xtfs->w_seq_set)) {
+ xtfs->w_seq_set = true;
+ xtfs->w_wantseq = inseq;
+ }
+ wantseq = xtfs->w_wantseq;
+
+ if (likely(inseq == wantseq))
+ return __reorder_this(xtfs, inskb, list);
+ else if (inseq < wantseq)
+ return __reorder_past(xtfs, inskb, freelist, fcount);
+ else if ((inseq - wantseq) < nslots)
+ return __reorder_future_fits(xtfs, inskb, freelist, fcount);
+ else
+ return __reorder_future_shifts(xtfs, inskb, list, freelist,
+ fcount);
+}
+
+/**
+ * iptfs_drop_timer() - Handle drop timer expiry.
+ *
+ * This is similar to our input function.
+ *
+ * The drop timer is set when we start an in progress reassembly, and also when
+ * we save a future packet in the window saved array.
+ *
+ * NOTE packets in the save window are always newer WRT drop times as
+ * they get further in the future. i.e. for:
+ *
+ * if slots (S0, S1, ... Sn) and `Dn` is the drop time for slot `Sn`,
+ * then D(n-1) <= D(n).
+ *
+ * So, regardless of why the timer is firing we can always discard any inprogress
+ * fragment; either it's the reassembly timer, or slot 0 is going to be
+ * dropped as S0 must have the most recent drop time, and slot 0 holds the
+ * continuation fragment of the in progress packet.
+ */
+static enum hrtimer_restart iptfs_drop_timer(struct hrtimer *me)
+{
+ struct sk_buff *skb, *next;
+ struct list_head freelist, list;
+ struct xfrm_iptfs_data *xtfs;
+ struct xfrm_state *x;
+ u32 count, fcount;
+
+ xtfs = container_of(me, typeof(*xtfs), drop_timer);
+ x = xtfs->x;
+
+ spin_lock(&xtfs->drop_lock);
+
+ INIT_LIST_HEAD(&list);
+ INIT_LIST_HEAD(&freelist);
+ fcount = 0;
+
+ /* Drop any in progress packet */
+
+ if (xtfs->ra_newskb) {
+ kfree_skb(xtfs->ra_newskb);
+ xtfs->ra_newskb = NULL;
+ }
+
+ /* Now drop as many packets as we should from the reordering window
+ * saved array
+ */
+ count = xtfs->w_savedlen ? __reorder_drop(xtfs, &list) : 0;
+
+ spin_unlock(&xtfs->drop_lock);
+
+ if (count) {
+ list_for_each_entry_safe(skb, next, &list, list) {
+ skb_list_del_init(skb);
+ (void)iptfs_input_ordered(x, skb);
+ }
+ }
+ return HRTIMER_NORESTART;
+}
+
+/**
+ * iptfs_input() - handle receipt of iptfs payload
+ * @x: xfrm state.
+ * @skb: the packet.
+ *
+ * We have an IPTFS payload order it if needed, then process newly in order
+ * packetsA.
+ */
+static int iptfs_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct list_head freelist, list;
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+ struct sk_buff *next;
+ u32 count, fcount;
+
+ /* Fast path for no reorder window. */
+ if (xtfs->cfg.reorder_win_size == 0) {
+ iptfs_input_ordered(x, skb);
+ goto done;
+ }
+
+ /* Fetch list of in-order packets from the reordering window as well as
+ * a list of buffers we need to now free.
+ */
+ INIT_LIST_HEAD(&list);
+ INIT_LIST_HEAD(&freelist);
+ fcount = 0;
+
+ spin_lock(&xtfs->drop_lock);
+ count = iptfs_input_reorder(xtfs, skb, &list, &freelist, &fcount);
+ spin_unlock(&xtfs->drop_lock);
+
+ if (count) {
+ list_for_each_entry_safe(skb, next, &list, list) {
+ skb_list_del_init(skb);
+ (void)iptfs_input_ordered(x, skb);
+ }
+ }
+
+ if (fcount) {
+ list_for_each_entry_safe(skb, next, &freelist, list) {
+ skb_list_del_init(skb);
+ kfree_skb(skb);
+ }
+ }
+done:
+ /* We always have dealt with the input SKB, either we are re-using it,
+ * or we have freed it. Return EINPROGRESS so that xfrm_input stops
+ * processing it.
+ */
+ return -EINPROGRESS;
+}
+
+/* ================================= */
+/* IPTFS Sending (ingress) Functions */
+/* ================================= */
+
+/* ------------------------- */
+/* Enqueue to send functions */
+/* ------------------------- */
+
+/**
+ * iptfs_enqueue() - enqueue packet if ok to send.
+ * @xtfs: xtfs state
+ * @skb: the packet
+ *
+ * Return: true if packet enqueued.
+ */
+static bool iptfs_enqueue(struct xfrm_iptfs_data *xtfs, struct sk_buff *skb)
+{
+ u64 newsz = xtfs->queue_size + skb->len;
+ struct iphdr *iph;
+
+ assert_spin_locked(&xtfs->x->lock);
+
+ if (newsz > xtfs->cfg.max_queue_size)
+ return false;
+
+ /* Set ECN CE if we are above our ECN queue threshold */
+ if (newsz > xtfs->ecn_queue_size) {
+ iph = ip_hdr(skb);
+ if (iph->version == 4)
+ IP_ECN_set_ce(iph);
+ else if (iph->version == 6)
+ IP6_ECN_set_ce(skb, ipv6_hdr(skb));
+ }
+
+ __skb_queue_tail(&xtfs->queue, skb);
+ xtfs->queue_size += skb->len;
+ return true;
+}
+
+static int iptfs_get_cur_pmtu(struct xfrm_state *x, struct xfrm_iptfs_data *xtfs,
+ struct sk_buff *skb)
+{
+ struct xfrm_dst *xdst = (struct xfrm_dst *)skb_dst(skb);
+ u32 payload_mtu = xtfs->payload_mtu;
+ u32 pmtu = __iptfs_get_inner_mtu(x, xdst->child_mtu_cached);
+
+ if (payload_mtu && payload_mtu < pmtu)
+ pmtu = payload_mtu;
+
+ return pmtu;
+}
+
+static int iptfs_is_too_big(struct sock *sk, struct sk_buff *skb, u32 pmtu)
+{
+ if (skb->len <= pmtu)
+ return 0;
+
+ /* We only send ICMP too big if the user has configured us as
+ * dont-fragment.
+ */
+ XFRM_INC_STATS(dev_net(skb->dev), LINUX_MIB_XFRMOUTERROR);
+
+ if (sk) {
+ xfrm_local_error(skb, pmtu);
+ } else if (ip_hdr(skb)->version == 4) {
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+ htonl(pmtu));
+ } else {
+ WARN_ON_ONCE(ip_hdr(skb)->version != 6);
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, pmtu);
+ }
+ return 1;
+}
+
+/* IPv4/IPv6 packet ingress to IPTFS tunnel, arrange to send in IPTFS payload
+ * (i.e., aggregating or fragmenting as appropriate).
+ * This is set in dst->output for an SA.
+ */
+static int iptfs_output_collect(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct xfrm_state *x = dst->xfrm;
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+ struct sk_buff *segs, *nskb;
+ u32 count, qcount;
+ u32 pmtu = 0;
+ bool ok = true;
+ bool was_gso;
+
+ /* We have hooked into dst_entry->output which means we have skipped the
+ * protocol specific netfilter (see xfrm4_output, xfrm6_output).
+ * when our timer runs we will end up calling xfrm_output directly on
+ * the encapsulated traffic.
+ *
+ * For both cases this is the NF_INET_POST_ROUTING hook which allows
+ * changing the skb->dst entry which then may not be xfrm based anymore
+ * in which case a REROUTED flag is set. and dst_output is called.
+ *
+ * For IPv6 we are also skipping fragmentation handling for local
+ * sockets, which may or may not be good depending on our tunnel DF
+ * setting. Normally with fragmentation supported we want to skip this
+ * fragmentation.
+ */
+
+ BUG_ON(!xtfs);
+
+ if (xtfs->cfg.dont_frag)
+ pmtu = iptfs_get_cur_pmtu(x, xtfs, skb);
+
+ /* Break apart GSO skbs. If the queue is nearing full then we want the
+ * accounting and queuing to be based on the individual packets not on the
+ * aggregate GSO buffer.
+ */
+ was_gso = skb_is_gso(skb);
+ if (!was_gso) {
+ segs = skb;
+ } else {
+ segs = skb_gso_segment(skb, 0);
+ if (IS_ERR_OR_NULL(segs)) {
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+ kfree_skb(skb);
+ return PTR_ERR(segs);
+ }
+ consume_skb(skb);
+ skb = NULL;
+ }
+
+ count = 0;
+ qcount = 0;
+
+ /* We can be running on multiple cores and from the network softirq or
+ * from user context depending on where the packet is coming from.
+ */
+ spin_lock_bh(&x->lock);
+
+ skb_list_walk_safe(segs, skb, nskb) {
+ skb_mark_not_on_list(skb);
+ count++;
+
+ /* Once we drop due to no queue space we continue to drop the
+ * rest of the packets from that GRO.
+ */
+ if (!ok) {
+nospace:
+ trace_iptfs_no_queue_space(skb, xtfs, pmtu, was_gso);
+ XFRM_INC_STATS(dev_net(skb->dev), LINUX_MIB_XFRMOUTNOQSPACE);
+ kfree_skb_reason(skb, SKB_DROP_REASON_FULL_RING);
+ continue;
+ }
+
+ /* If the user indicated no iptfs fragmenting check before
+ * enqueue.
+ */
+ if (xtfs->cfg.dont_frag && iptfs_is_too_big(sk, skb, pmtu)) {
+ trace_iptfs_too_big(skb, xtfs, pmtu, was_gso);
+ kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
+ continue;
+ }
+
+ /* Enqueue to send in tunnel */
+
+ ok = iptfs_enqueue(xtfs, skb);
+ if (!ok)
+ goto nospace;
+
+ trace_iptfs_enqueue(skb, xtfs, pmtu, was_gso);
+ qcount++;
+ }
+
+ /* Start a delay timer if we don't have one yet */
+ if (!hrtimer_is_queued(&xtfs->iptfs_timer)) {
+ /* softirq blocked lest the timer fire and interrupt us */
+ BUG_ON(!in_interrupt());
+ hrtimer_start(&xtfs->iptfs_timer, xtfs->init_delay_ns,
+ IPTFS_HRTIMER_MODE);
+
+ xtfs->iptfs_settime = ktime_get_raw_fast_ns();
+ trace_iptfs_timer_start(xtfs, xtfs->init_delay_ns);
+ }
+
+ spin_unlock_bh(&x->lock);
+ return 0;
+}
+
+/* -------------------------- */
+/* Dequeue and send functions */
+/* -------------------------- */
+
+static void iptfs_output_prepare_skb(struct sk_buff *skb, u32 blkoff)
+{
+ struct ip_iptfs_hdr *h;
+ size_t hsz = sizeof(*h);
+
+ /* now reset values to be pointing at the rest of the packets */
+ h = skb_push(skb, hsz);
+ memset(h, 0, hsz);
+ if (blkoff)
+ h->block_offset = htons(blkoff);
+
+ /* network_header current points at the inner IP packet
+ * move it to the iptfs header
+ */
+ skb->transport_header = skb->network_header;
+ skb->network_header -= hsz;
+
+ IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
+
+ /* xfrm[46]_prepare_output sets skb->protocol here, but the resulting
+ * called ip[6]_output functions also set this value as appropriate so
+ * seems unnecessary
+ *
+ * skb->protocol = htons(ETH_P_IP) or htons(ETH_P_IPV6);
+ */
+}
+
+/**
+ * iptfs_copy_create_frag() - create an inner fragment skb.
+ * @st: The source packet data.
+ * @offset: offset in @st of the new fragment data.
+ * @copy_len: the amount of data to copy from @st.
+ *
+ * Create a new skb holding a single IPTFS inner packet fragment. @copy_len must
+ * not be greater than the max fragment size.
+ *
+ * Return: the new fragment skb or an ERR_PTR().
+ */
+static struct sk_buff *iptfs_copy_create_frag(struct skb_seq_state *st,
+ u32 offset, u32 copy_len)
+{
+ struct sk_buff *src = st->root_skb;
+ struct sk_buff *skb;
+ int err;
+
+ skb = iptfs_alloc_skb(src, copy_len, true);
+ if (!skb)
+ return ERR_PTR(-ENOMEM);
+
+ /* Now copy `copy_len` data from src */
+ err = skb_copy_bits_seq(st, offset, skb_put(skb, copy_len), copy_len);
+ if (err) {
+ XFRM_INC_STATS(dev_net(src->dev), LINUX_MIB_XFRMOUTERROR);
+ kfree_skb(skb);
+ return ERR_PTR(err);
+ }
+
+ return skb;
+}
+
+/**
+ * iptfs_copy_create_frags() - create and send N-1 fragments of a larger skb.
+ * @skbp: the source packet skb (IN), skb holding the last fragment in
+ * the fragment stream (OUT).
+ * @xtfs: IPTFS SA state.
+ * @mtu: the max IPTFS fragment size.
+ *
+ * This function is responsible for fragmenting a larger inner packet into a
+ * sequence of IPTFS payload packets. The last fragment is returned rather than
+ * being sent so that the caller can append more inner packets (aggregation) if
+ * there is room.
+ */
+static int iptfs_copy_create_frags(struct sk_buff **skbp,
+ struct xfrm_iptfs_data *xtfs, u32 mtu)
+{
+ struct skb_seq_state skbseq;
+ struct list_head sublist;
+ struct sk_buff *skb = *skbp;
+ struct sk_buff *nskb = *skbp;
+ u32 copy_len, offset;
+ u32 to_copy = skb->len - mtu;
+ u32 blkoff = 0;
+ int err = 0;
+
+ INIT_LIST_HEAD(&sublist);
+
+ BUG_ON(skb->len <= mtu);
+ skb_prepare_seq_read(skb, 0, skb->len, &skbseq);
+
+ /* A trimmed `skb` will be sent as the first fragment, later. */
+ offset = mtu;
+ to_copy = skb->len - offset;
+ while (to_copy) {
+ /* Send all but last fragment to allow agg. append */
+ trace_iptfs_first_fragmenting(nskb, mtu, to_copy, NULL);
+ list_add_tail(&nskb->list, &sublist);
+
+ /* FUTURE: if the packet has an odd/non-aligning length we could
+ * send less data in the penultimate fragment so that the last
+ * fragment then ends on an aligned boundary.
+ */
+ copy_len = to_copy <= mtu ? to_copy : mtu;
+ nskb = iptfs_copy_create_frag(&skbseq, offset, copy_len);
+ if (IS_ERR(nskb)) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMOUTERROR);
+ skb_abort_seq_read(&skbseq);
+ err = PTR_ERR(nskb);
+ nskb = NULL;
+ break;
+ }
+ iptfs_output_prepare_skb(nskb, to_copy);
+ offset += copy_len;
+ to_copy -= copy_len;
+ blkoff = to_copy;
+ }
+ skb_abort_seq_read(&skbseq);
+
+ /* return last fragment that will be unsent (or NULL) */
+ *skbp = nskb;
+ if (nskb)
+ trace_iptfs_first_final_fragment(nskb, mtu, blkoff, NULL);
+
+ /* trim the original skb to MTU */
+ if (!err)
+ err = pskb_trim(skb, mtu);
+
+ if (err) {
+ /* Free all frags. Don't bother sending a partial packet we will
+ * never complete.
+ */
+ kfree_skb(nskb);
+ list_for_each_entry_safe(skb, nskb, &sublist, list) {
+ skb_list_del_init(skb);
+ kfree_skb(skb);
+ }
+ return err;
+ }
+
+ /* prepare the initial fragment with an iptfs header */
+ iptfs_output_prepare_skb(skb, 0);
+
+ /* Send all but last fragment. */
+ list_for_each_entry_safe(skb, nskb, &sublist, list) {
+ skb_list_del_init(skb);
+ xfrm_output(NULL, skb);
+ }
+
+ return 0;
+}
+
+/**
+ * iptfs_first_should_copy() - determine if we should copy packet data.
+ * @first_skb: the first skb in the packet
+ * @mtu: the MTU.
+ *
+ * Determine if we should create subsequent skbs to hold the remaining data from
+ * a large inner packet by copying the packet data, or cloning the original skb
+ * and adjusting the offsets.
+ */
+static bool iptfs_first_should_copy(struct sk_buff *first_skb, u32 mtu)
+{
+ u32 frag_copy_max;
+
+ /* If we have less than frag_copy_max for remaining packet we copy
+ * those tail bytes as it is more efficient.
+ */
+ frag_copy_max = mtu <= IPTFS_FRAG_COPY_MAX ? mtu : IPTFS_FRAG_COPY_MAX;
+ if ((int)first_skb->len - (int)mtu < (int)frag_copy_max)
+ return true;
+
+ /* If we have non-linear skb just use copy */
+ if (skb_is_nonlinear(first_skb))
+ return true;
+
+ /* So we have a simple linear skb, easy to clone and share */
+ return false;
+}
+
+/**
+ * iptfs_first_skb() - handle the first dequeued inner packet for output
+ * @skbp: the source packet skb (IN), skb holding the last fragment in
+ * the fragment stream (OUT).
+ * @xtfs: IPTFS SA state.
+ * @mtu: the max IPTFS fragment size.
+ *
+ * This function is responsible for fragmenting a larger inner packet into a
+ * sequence of IPTFS payload packets. If it needs to fragment into subsequent
+ * skb's, it will either do so by copying or cloning.
+ *
+ * The last fragment is returned rather than being sent so that the caller can
+ * append more inner packets (aggregation) if there is room.
+ *
+ */
+static int iptfs_first_skb(struct sk_buff **skbp, struct xfrm_iptfs_data *xtfs,
+ u32 mtu)
+{
+ struct sk_buff *skb = *skbp;
+ int err;
+
+ /* Classic ESP skips the don't fragment ICMP error if DF is clear on
+ * the inner packet or ignore_df is set. Otherwise it will send an ICMP
+ * or local error if the inner packet won't fit it's MTU.
+ *
+ * With IPTFS we do not care about the inner packet DF bit. If the
+ * tunnel is configured to "don't fragment" we error back if things
+ * don't fit in our max packet size. Otherwise we iptfs-fragment as
+ * normal.
+ */
+
+ /* The opportunity for HW offload has ended */
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ err = skb_checksum_help(skb);
+ if (err)
+ return err;
+ }
+
+ /* We've split these up before queuing */
+ BUG_ON(skb_is_gso(skb));
+
+ trace_iptfs_first_dequeue(skb, mtu, 0, ip_hdr(skb));
+
+ /* Simple case -- it fits. `mtu` accounted for all the overhead
+ * including the basic IPTFS header.
+ */
+ if (skb->len <= mtu) {
+ iptfs_output_prepare_skb(skb, 0);
+ return 0;
+ }
+
+ BUG_ON(xtfs->cfg.dont_frag);
+
+ if (iptfs_first_should_copy(skb, mtu))
+ return iptfs_copy_create_frags(skbp, xtfs, mtu);
+
+ /* For now we always copy */
+ return iptfs_copy_create_frags(skbp, xtfs, mtu);
+}
+
+static struct sk_buff **iptfs_rehome_fraglist(struct sk_buff **nextp,
+ struct sk_buff *child)
+{
+ u32 fllen = 0;
+
+ BUG_ON(!skb_has_frag_list(child));
+
+ /* It might be possible to account for a frag list in addition to page
+ * fragment if it's a valid state to be in. The page fragments size
+ * should be kept as data_len so only the frag_list size is removed,
+ * this must be done above as well took
+ */
+ BUG_ON(skb_shinfo(child)->nr_frags);
+ *nextp = skb_shinfo(child)->frag_list;
+ while (*nextp) {
+ fllen += (*nextp)->len;
+ nextp = &(*nextp)->next;
+ }
+ skb_frag_list_init(child);
+ BUG_ON(fllen > child->data_len);
+ child->len -= fllen;
+ child->data_len -= fllen;
+
+ return nextp;
+}
+
+static void iptfs_consume_frags(struct sk_buff *to, struct sk_buff *from)
+{
+ struct skb_shared_info *fromi = skb_shinfo(from);
+ struct skb_shared_info *toi = skb_shinfo(to);
+ unsigned int new_truesize;
+
+ /* If we have data in a head page, grab it */
+ if (!skb_headlen(from)) {
+ new_truesize = SKB_TRUESIZE(skb_end_offset(from));
+ } else {
+ skb_head_to_frag(from, &toi->frags[toi->nr_frags]);
+ skb_frag_ref(to, toi->nr_frags++);
+ new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff));
+ }
+
+ /* Move any other page fragments rather than copy */
+ memcpy(&toi->frags[toi->nr_frags], fromi->frags,
+ sizeof(fromi->frags[0]) * fromi->nr_frags);
+ toi->nr_frags += fromi->nr_frags;
+ fromi->nr_frags = 0;
+ from->data_len = 0;
+ from->len = 0;
+ to->truesize += from->truesize - new_truesize;
+ from->truesize = new_truesize;
+
+ /* We are done with this SKB */
+ consume_skb(from);
+}
+
+static void iptfs_output_queued(struct xfrm_state *x, struct sk_buff_head *list)
+{
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+ u32 payload_mtu = xtfs->payload_mtu;
+ struct sk_buff *skb, *skb2, **nextp;
+ struct skb_shared_info *shi, *shi2;
+
+ /* For now we are just outputting packets as fast as we can, so if we
+ * are fragmenting we will do so until the last inner packet has been
+ * consumed.
+ *
+ * When we are fragmenting we need to output all outer packets that
+ * contain the fragments of a single inner packet, consecutively (ESP
+ * seq-wise). So we need a lock to keep another CPU from sending the
+ * next batch of packets (it's `list`) and trying to output those, while
+ * we output our `list` resuling with interleaved non-spec-client inner
+ * packet streams. Thus we need to lock the IPTFS output on a per SA
+ * basis while we process this list.
+ */
+
+ /* NOTE: for the future, for timed packet sends, if our queue is not
+ * growing longer (i.e., we are keeping up) and a packet we are about to
+ * fragment will not fragment in then next outer packet, we might consider
+ * holding on to it to send whole in the next slot. The question then is
+ * does this introduce a continuous delay in the inner packet stream
+ * with certain packet rates and sizes?
+ */
+
+ /* and send them on their way */
+
+ while ((skb = __skb_dequeue(list))) {
+ struct xfrm_dst *xdst = (struct xfrm_dst *)skb_dst(skb);
+ u32 mtu = __iptfs_get_inner_mtu(x, xdst->child_mtu_cached);
+ bool share_ok = true;
+ int remaining;
+
+ /* protocol comes to us cleared sometimes */
+ skb->protocol = x->outer_mode.family == AF_INET ?
+ htons(ETH_P_IP) :
+ htons(ETH_P_IPV6);
+
+ if (payload_mtu && payload_mtu < mtu)
+ mtu = payload_mtu;
+
+ if (skb->len > mtu && xtfs->cfg.dont_frag) {
+ /* We handle this case before enqueueing so we are only
+ * here b/c MTU changed after we enqueued before we
+ * dequeued, just drop these.
+ */
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMOUTERROR);
+
+ trace_iptfs_first_toobig(skb, mtu, 0, ip_hdr(skb));
+ kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
+ continue;
+ }
+
+ /* iptfs_first_skb will free skb on error as well */
+ if (iptfs_first_skb(&skb, xtfs, mtu))
+ continue;
+
+ /* The returned skb is the last IPTFS fragment, it has it's
+ * IPTFS header included and it's blkoff set just past the end
+ * fragment data if needed. The space remaining to send more
+ * inner packet data is `mtu` - (skb->len - sizeof iptfs
+ * header). This is b/c the `mtu` value has the basic IPTFS
+ * header len accounted for, and we added that header to the skb
+ * so it is a part of skb->len, thus we subtract it from the skb
+ * length.
+ */
+ remaining = mtu - (skb->len - sizeof(struct ip_iptfs_hdr));
+
+ /* Re-home nested fragment lists. */
+ shi = skb_shinfo(skb);
+ nextp = &shi->frag_list;
+ while (*nextp) {
+ if (skb_has_frag_list(*nextp))
+ nextp = iptfs_rehome_fraglist(&(*nextp)->next,
+ *nextp);
+ else
+ nextp = &(*nextp)->next;
+ }
+
+ if (shi->frag_list || skb_cloned(skb) || skb_shared(skb))
+ share_ok = false;
+
+ /* See if we have enough space to simply append.
+ *
+ * NOTE: Maybe do not append if we will be mis-aligned,
+ * SW-based endpoints will probably have to copy in this
+ * case.
+ */
+ while ((skb2 = skb_peek(list))) {
+ trace_iptfs_ingress_nth_peek(skb2, remaining);
+ if (skb2->len > remaining)
+ break;
+
+ __skb_unlink(skb2, list);
+
+ /* The opportunity for HW offload has ended, if we
+ * don't have a cksum in the packet we need to add one
+ * before encap and transmit.
+ */
+ if (skb2->ip_summed == CHECKSUM_PARTIAL) {
+ if (skb_checksum_help(skb2)) {
+ XFRM_INC_STATS(dev_net(skb_dst(skb2)->dev),
+ LINUX_MIB_XFRMOUTERROR);
+ kfree_skb(skb2);
+ continue;
+ }
+ }
+
+ /* skb->pp_recycle is passed to __skb_flag_unref for all
+ * frag pages so we can only share pages with skb's who
+ * match ourselves.
+ */
+ shi2 = skb_shinfo(skb2);
+ if (share_ok &&
+ (shi2->frag_list ||
+ (!skb2->head_frag && skb_headlen(skb)) ||
+ skb->pp_recycle != skb2->pp_recycle ||
+ skb_zcopy(skb2) ||
+ (shi->nr_frags + shi2->nr_frags + 1 > MAX_SKB_FRAGS)))
+ share_ok = false;
+
+ /* do acct so we can free skb2 in share case */
+ skb->data_len += skb2->len;
+ skb->len += skb2->len;
+ remaining -= skb2->len;
+
+ trace_iptfs_ingress_nth_add(skb2, share_ok);
+
+ if (share_ok) {
+ iptfs_consume_frags(skb, skb2);
+ } else {
+ /* link on the frag_list */
+ *nextp = skb2;
+ nextp = &skb2->next;
+ BUG_ON(*nextp);
+ if (skb_has_frag_list(skb2))
+ nextp = iptfs_rehome_fraglist(nextp,
+ skb2);
+ skb->truesize += skb2->truesize;
+ }
+ }
+
+ /* Consider fragmenting this skb2 that didn't fit. For demand
+ * driven variable sized IPTFS pkts, though this isn't buying
+ * a whole lot, especially if we are doing a copy which waiting
+ * to send in a new pkt would not.
+ */
+
+ xfrm_output(NULL, skb);
+ }
+}
+
+static enum hrtimer_restart iptfs_delay_timer(struct hrtimer *me)
+{
+ struct sk_buff_head list;
+ struct xfrm_iptfs_data *xtfs;
+ struct xfrm_state *x;
+ time64_t settime;
+ size_t osize;
+
+ xtfs = container_of(me, typeof(*xtfs), iptfs_timer);
+ x = xtfs->x;
+
+ /* Process all the queued packets
+ *
+ * softirq execution order: timer > tasklet > hrtimer
+ *
+ * Network rx will have run before us giving one last chance to queue
+ * ingress packets for us to process and transmit.
+ */
+
+ spin_lock(&x->lock);
+ __skb_queue_head_init(&list);
+ skb_queue_splice_init(&xtfs->queue, &list);
+ osize = xtfs->queue_size;
+ xtfs->queue_size = 0;
+ settime = xtfs->iptfs_settime;
+ spin_unlock(&x->lock);
+
+ /* After the above unlock, packets can begin queuing again, and the
+ * timer can be set again, from another CPU either in softirq or user
+ * context (not from this one since we are running at softirq level
+ * already).
+ */
+
+ trace_iptfs_timer_expire(xtfs,
+ (unsigned long long)(ktime_get_raw_fast_ns() - settime));
+
+ iptfs_output_queued(x, &list);
+
+ return HRTIMER_NORESTART;
+}
+
+/**
+ * iptfs_encap_add_ipv4() - add outer encaps
+ *
+ * This was originally taken from xfrm4_tunnel_encap_add. The reason for the
+ * copy is that IP-TFS/AGGFRAG can have different functionality for how to set
+ * the TOS/DSCP bits. Sets the protocol to a different value and doesn't do
+ * anything with inner headers as they aren't pointing into a normal IP
+ * singleton inner packet.
+ */
+static int iptfs_encap_add_ipv4(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct iphdr *top_iph;
+ int flags;
+
+ skb_reset_inner_network_header(skb);
+ skb_reset_inner_transport_header(skb);
+
+ skb_set_network_header(skb, -(x->props.header_len - x->props.enc_hdr_len));
+ skb->mac_header = skb->network_header + offsetof(struct iphdr, protocol);
+ skb->transport_header = skb->network_header + sizeof(*top_iph);
+
+ top_iph = ip_hdr(skb);
+ top_iph->ihl = 5;
+ top_iph->version = 4;
+ top_iph->protocol = IPPROTO_AGGFRAG;
+
+ /* As we have 0, fractional, 1 or N inner packets there's no obviously
+ * correct DSCP mapping to inherit. ECN should be cleared per RFC9347
+ * 3.1.
+ */
+ top_iph->tos = 0;
+
+ flags = x->props.flags;
+ top_iph->frag_off = htons(IP_DF);
+ top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
+ top_iph->saddr = x->props.saddr.a4;
+ top_iph->daddr = x->id.daddr.a4;
+ ip_select_ident(dev_net(dst->dev), skb, NULL);
+
+ return 0;
+}
+
+/**
+ * iptfs_encap_add_ipv6() - add outer encaps
+ *
+ * This was originally taken from xfrm6_tunnel_encap_add. The reason for the
+ * copy is that IP-TFS/AGGFRAG can have different functionality for how to set
+ * the flow label and TOS/DSCP bits. It also sets the protocol to a different
+ * value and doesn't do anything with inner headers as they aren't pointing into
+ * a normal IP singleton inner packet.
+ */
+static int iptfs_encap_add_ipv6(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ struct ipv6hdr *top_iph;
+ int dsfield;
+
+ skb_reset_inner_network_header(skb);
+ skb_reset_inner_transport_header(skb);
+
+ skb_set_network_header(skb,
+ -x->props.header_len + x->props.enc_hdr_len);
+ skb->mac_header = skb->network_header +
+ offsetof(struct ipv6hdr, nexthdr);
+ skb->transport_header = skb->network_header + sizeof(*top_iph);
+
+ top_iph = ipv6_hdr(skb);
+ top_iph->version = 6;
+ top_iph->priority = 0;
+ memset(top_iph->flow_lbl, 0, sizeof(top_iph->flow_lbl));
+ top_iph->nexthdr = IPPROTO_AGGFRAG;
+
+ /* As we have 0, fractional, 1 or N inner packets there's no obviously
+ * correct DSCP mapping to inherit. ECN should be cleared per RFC9347
+ * 3.1.
+ */
+ dsfield = 0;
+ ipv6_change_dsfield(top_iph, 0, dsfield);
+
+ top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
+ top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
+ top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
+
+ return 0;
+}
+
+/**
+ * iptfs_prepare_output() - prepare the skb for output
+ *
+ * Return: Error value, if 0 then skb values should be as follows:
+ * - transport_header should point at ESP header
+ * - network_header should point at Outer IP header
+ * - mac_header should point at protocol/nexthdr of the outer IP
+ */
+static int iptfs_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ if (x->outer_mode.family == AF_INET)
+ return iptfs_encap_add_ipv4(x, skb);
+ if (x->outer_mode.family == AF_INET6) {
+#if IS_ENABLED(CONFIG_IPV6)
+ return iptfs_encap_add_ipv6(x, skb);
+#else
+ WARN_ON_ONCE(1);
+ return -EAFNOSUPPORT;
+#endif
+ }
+ WARN_ON_ONCE(1);
+ return -EOPNOTSUPP;
+}
+
+/* ========================== */
+/* State Management Functions */
+/* ========================== */
+
+/**
+ * __iptfs_get_inner_mtu() - return inner MTU with no fragmentation.
+ */
+static u32 __iptfs_get_inner_mtu(struct xfrm_state *x, int outer_mtu)
+{
+ struct crypto_aead *aead;
+ u32 blksize;
+
+ aead = x->data;
+ blksize = ALIGN(crypto_aead_blocksize(aead), 4);
+ return ((outer_mtu - x->props.header_len - crypto_aead_authsize(aead)) &
+ ~(blksize - 1)) - 2;
+}
+
+/**
+ * iptfs_get_mtu() - return the inner MTU for an IPTFS xfrm.
+ * @x: XFRM state.
+ * @outer_mtu: Outer MTU for the encapsulated packet.
+ *
+ * Return: Correct MTU taking in to account the encap overhead.
+ */
+static u32 iptfs_get_inner_mtu(struct xfrm_state *x, int outer_mtu)
+{
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+
+ /* If not dont-frag we have no MTU */
+ if (!xtfs->cfg.dont_frag)
+ return x->outer_mode.family == AF_INET ? IP_MAX_MTU :
+ IP6_MAX_MTU;
+ return __iptfs_get_inner_mtu(x, outer_mtu);
+}
+
+/**
+ * iptfs_user_init() - initialize the SA with IPTFS options from netlink.
+ */
+static int iptfs_user_init(struct net *net, struct xfrm_state *x,
+ struct nlattr **attrs)
+{
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+ struct xfrm_iptfs_config *xc;
+
+ if (x->props.mode != XFRM_MODE_IPTFS)
+ return -EINVAL;
+
+ xc = &xtfs->cfg;
+ xc->reorder_win_size = net->xfrm.sysctl_iptfs_rewin;
+ xc->max_queue_size = net->xfrm.sysctl_iptfs_maxqsize;
+ xc->init_delay_us = net->xfrm.sysctl_iptfs_idelay;
+ xc->drop_time_us = net->xfrm.sysctl_iptfs_drptime;
+
+ if (attrs[XFRMA_IPTFS_DONT_FRAG])
+ xc->dont_frag = true;
+ if (attrs[XFRMA_IPTFS_REORD_WIN])
+ xc->reorder_win_size =
+ nla_get_u16(attrs[XFRMA_IPTFS_REORD_WIN]);
+ /* saved array is for saving 1..N seq nums from wantseq */
+ if (xc->reorder_win_size)
+ xtfs->w_saved = kcalloc(xc->reorder_win_size,
+ sizeof(*xtfs->w_saved), GFP_KERNEL);
+ if (attrs[XFRMA_IPTFS_PKT_SIZE]) {
+ xc->pkt_size = nla_get_u32(attrs[XFRMA_IPTFS_PKT_SIZE]);
+ if (!xc->pkt_size)
+ xtfs->payload_mtu = 0;
+ else if (xc->pkt_size > x->props.header_len)
+ xtfs->payload_mtu = xc->pkt_size - x->props.header_len;
+ else
+ return -EINVAL;
+ }
+ if (attrs[XFRMA_IPTFS_MAX_QSIZE])
+ xc->max_queue_size = nla_get_u32(attrs[XFRMA_IPTFS_MAX_QSIZE]);
+ if (attrs[XFRMA_IPTFS_DROP_TIME])
+ xc->drop_time_us = nla_get_u32(attrs[XFRMA_IPTFS_DROP_TIME]);
+ if (attrs[XFRMA_IPTFS_INIT_DELAY])
+ xc->init_delay_us = nla_get_u32(attrs[XFRMA_IPTFS_INIT_DELAY]);
+
+ xtfs->ecn_queue_size = (u64)xc->max_queue_size * 95 / 100;
+ xtfs->drop_time_ns = xc->drop_time_us * NSECS_IN_USEC;
+ xtfs->init_delay_ns = xc->init_delay_us * NSECS_IN_USEC;
+
+ return 0;
+}
+
+static int iptfs_copy_to_user(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+ struct xfrm_iptfs_config *xc = &xtfs->cfg;
+ int ret;
+
+ if (xc->dont_frag) {
+ ret = nla_put_flag(skb, XFRMA_IPTFS_DONT_FRAG);
+ if (ret)
+ return ret;
+ }
+ ret = nla_put_u16(skb, XFRMA_IPTFS_REORD_WIN, xc->reorder_win_size);
+ if (ret)
+ return ret;
+ ret = nla_put_u32(skb, XFRMA_IPTFS_PKT_SIZE, xc->pkt_size);
+ if (ret)
+ return ret;
+ ret = nla_put_u32(skb, XFRMA_IPTFS_MAX_QSIZE, xc->max_queue_size);
+ if (ret)
+ return ret;
+ ret = nla_put_u32(skb, XFRMA_IPTFS_DROP_TIME, xc->drop_time_us);
+ if (ret)
+ return ret;
+ ret = nla_put_u32(skb, XFRMA_IPTFS_INIT_DELAY, xc->init_delay_us);
+ return ret;
+}
+
+static int iptfs_create_state(struct xfrm_state *x)
+{
+ struct xfrm_iptfs_data *xtfs;
+
+ xtfs = kzalloc(sizeof(*xtfs), GFP_KERNEL);
+ if (!xtfs)
+ return -ENOMEM;
+ x->mode_data = xtfs;
+
+ xtfs->x = x;
+
+ __skb_queue_head_init(&xtfs->queue);
+ xtfs->init_delay_ns = xtfs->cfg.init_delay_us * NSECS_IN_USEC;
+ hrtimer_init(&xtfs->iptfs_timer, CLOCK_MONOTONIC, IPTFS_HRTIMER_MODE);
+ xtfs->iptfs_timer.function = iptfs_delay_timer;
+
+ xtfs->drop_time_ns = xtfs->cfg.drop_time_us * NSECS_IN_USEC;
+ spin_lock_init(&xtfs->drop_lock);
+ hrtimer_init(&xtfs->drop_timer, CLOCK_MONOTONIC, IPTFS_HRTIMER_MODE);
+ xtfs->drop_timer.function = iptfs_drop_timer;
+
+ /* Modify type (esp) adjustment values */
+
+ if (x->props.family == AF_INET)
+ x->props.header_len += sizeof(struct iphdr) + sizeof(struct ip_iptfs_hdr);
+ else if (x->props.family == AF_INET6)
+ x->props.header_len += sizeof(struct ipv6hdr) + sizeof(struct ip_iptfs_hdr);
+ x->props.enc_hdr_len = sizeof(struct ip_iptfs_hdr);
+
+ return 0;
+}
+
+static void iptfs_delete_state(struct xfrm_state *x)
+{
+ struct xfrm_iptfs_data *xtfs = x->mode_data;
+
+ if (IS_ERR_OR_NULL(xtfs))
+ return;
+
+ spin_lock(&xtfs->drop_lock);
+ hrtimer_cancel(&xtfs->iptfs_timer);
+ hrtimer_cancel(&xtfs->drop_timer);
+ spin_unlock(&xtfs->drop_lock);
+
+ kfree_sensitive(xtfs->w_saved);
+ kfree_sensitive(xtfs);
+}
+
+static const struct xfrm_mode_cbs iptfs_mode_cbs = {
+ .owner = THIS_MODULE,
+ .create_state = iptfs_create_state,
+ .delete_state = iptfs_delete_state,
+ .user_init = iptfs_user_init,
+ .copy_to_user = iptfs_copy_to_user,
+ .get_inner_mtu = iptfs_get_inner_mtu,
+ .input = iptfs_input,
+ .output = iptfs_output_collect,
+ .prepare_output = iptfs_prepare_output,
+};
+
+static int __init xfrm_iptfs_init(void)
+{
+ int err;
+
+ pr_info("xfrm_iptfs: IPsec IP-TFS tunnel mode module\n");
+
+ err = xfrm_register_mode_cbs(XFRM_MODE_IPTFS, &iptfs_mode_cbs);
+ if (err < 0)
+ pr_info("%s: can't register IP-TFS\n", __func__);
+
+ return err;
+}
+
+static void __exit xfrm_iptfs_fini(void)
+{
+ xfrm_unregister_mode_cbs(XFRM_MODE_IPTFS);
+}
+
+module_init(xfrm_iptfs_init);
+module_exit(xfrm_iptfs_fini);
+MODULE_LICENSE("GPL");
--
2.42.0
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