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Message-ID: <2ce25de74134e96dfa0b21a419e7c01f31c41226.1715807303.git.lorenzo@kernel.org>
Date: Wed, 15 May 2024 23:12:56 +0200
From: Lorenzo Bianconi <lorenzo@...nel.org>
To: bpf@...r.kernel.org
Cc: pablo@...filter.org,
kadlec@...filter.org,
davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com,
netfilter-devel@...r.kernel.org,
netdev@...r.kernel.org,
ast@...nel.org,
daniel@...earbox.net,
andrii@...nel.org,
lorenzo.bianconi@...hat.com,
toke@...hat.com,
fw@...len.de,
hawk@...nel.org,
horms@...nel.org,
donhunte@...hat.com
Subject: [PATCH bpf-next 3/4] samples/bpf: Add bpf sample to offload flowtable traffic to xdp
Introduce xdp_flowtable_offload bpf sample to offload sw flowtable logic
in xdp layer if hw flowtable is not available or does not support a
specific kind of traffic.
Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
---
samples/bpf/Makefile | 7 +-
samples/bpf/xdp_flowtable_offload.bpf.c | 592 +++++++++++++++++++++++
samples/bpf/xdp_flowtable_offload_user.c | 128 +++++
3 files changed, 726 insertions(+), 1 deletion(-)
create mode 100644 samples/bpf/xdp_flowtable_offload.bpf.c
create mode 100644 samples/bpf/xdp_flowtable_offload_user.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 9aa027b144df6..a3d089ca224d5 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -46,6 +46,7 @@ tprogs-y += xdp_fwd
tprogs-y += task_fd_query
tprogs-y += ibumad
tprogs-y += hbm
+tprogs-y += xdp_flowtable_offload
# Libbpf dependencies
LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf
@@ -98,6 +99,7 @@ ibumad-objs := ibumad_user.o
hbm-objs := hbm.o $(CGROUP_HELPERS)
xdp_router_ipv4-objs := xdp_router_ipv4_user.o $(XDP_SAMPLE)
+xdp_flowtable_offload-objs := xdp_flowtable_offload_user.o $(XDP_SAMPLE)
# Tell kbuild to always build the programs
always-y := $(tprogs-y)
@@ -306,6 +308,7 @@ $(obj)/$(TRACE_HELPERS) $(obj)/$(CGROUP_HELPERS) $(obj)/$(XDP_SAMPLE): | libbpf_
.PHONY: libbpf_hdrs
$(obj)/xdp_router_ipv4_user.o: $(obj)/xdp_router_ipv4.skel.h
+$(obj)/xdp_flowtable_offload_user.o: $(obj)/xdp_flowtable_offload.skel.h
$(obj)/tracex5.bpf.o: $(obj)/syscall_nrs.h
$(obj)/hbm_out_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
@@ -361,6 +364,7 @@ endef
CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
$(obj)/xdp_router_ipv4.bpf.o: $(obj)/xdp_sample.bpf.o
+$(obj)/xdp_flowtable_offload.bpf.o: $(obj)/xdp_sample.bpf.o
$(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/xdp_sample_shared.h
@echo " CLANG-BPF " $@
@@ -370,10 +374,11 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/x
-I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \
-c $(filter %.bpf.c,$^) -o $@
-LINKED_SKELS := xdp_router_ipv4.skel.h
+LINKED_SKELS := xdp_router_ipv4.skel.h xdp_flowtable_offload.skel.h
clean-files += $(LINKED_SKELS)
xdp_router_ipv4.skel.h-deps := xdp_router_ipv4.bpf.o xdp_sample.bpf.o
+xdp_flowtable_offload.skel.h-deps := xdp_flowtable_offload.bpf.o xdp_sample.bpf.o
LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
diff --git a/samples/bpf/xdp_flowtable_offload.bpf.c b/samples/bpf/xdp_flowtable_offload.bpf.c
new file mode 100644
index 0000000000000..728c859feefae
--- /dev/null
+++ b/samples/bpf/xdp_flowtable_offload.bpf.c
@@ -0,0 +1,592 @@
+/* Copyright (c) 2024 Lorenzo Bianconi <lorenzo@...nel.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include "vmlinux.h"
+#include "xdp_sample.bpf.h"
+#include "xdp_sample_shared.h"
+
+#define MAX_ERRNO 4095
+#define IS_ERR_VALUE(x) (unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO
+#define BIT(x) (1 << (x))
+
+#define ETH_P_IP 0x0800
+#define IP_MF 0x2000 /* "More Fragments" */
+#define IP_OFFSET 0x1fff /* "Fragment Offset" */
+
+#define IPV6_FLOWINFO_MASK __cpu_to_be32(0x0fffffff)
+
+#define CSUM_MANGLED_0 ((__sum16)0xffff)
+
+struct flow_offload_tuple_rhash *
+bpf_xdp_flow_offload_lookup(struct xdp_md *,
+ struct bpf_fib_lookup *, u32) __ksym;
+
+/* IP checksum utility routines */
+
+static __always_inline __u32 csum_add(__u32 csum, __u32 addend)
+{
+ __u32 res = csum + addend;
+
+ return res + (res < addend);
+}
+
+static __always_inline __u16 csum_fold(__u32 csum)
+{
+ csum = (csum & 0xffff) + (csum >> 16);
+ csum = (csum & 0xffff) + (csum >> 16);
+ return ~csum;
+}
+
+static __always_inline __u16 csum_replace4(__u32 csum, __u32 from, __u32 to)
+{
+ __u32 tmp = csum_add(~csum, ~from);
+
+ return csum_fold(csum_add(tmp, to));
+}
+
+static __always_inline __u16 csum_replace16(__u32 csum, __u32 *from, __u32 *to)
+{
+ __u32 diff[] = {
+ ~from[0], ~from[1], ~from[2], ~from[3],
+ to[0], to[1], to[2], to[3],
+ };
+
+ csum = bpf_csum_diff(0, 0, diff, sizeof(diff), ~csum);
+ return csum_fold(csum);
+}
+
+/* IP-TCP header utility routines */
+
+static __always_inline void ip_decrease_ttl(struct iphdr *iph)
+{
+ __u32 check = (__u32)iph->check;
+
+ check += (__u32)bpf_htons(0x0100);
+ iph->check = (__sum16)(check + (check >= 0xffff));
+ iph->ttl--;
+}
+
+static __always_inline bool
+xdp_flowtable_offload_check_iphdr(struct iphdr *iph)
+{
+ /* ip fragmented traffic */
+ if (iph->frag_off & bpf_htons(IP_MF | IP_OFFSET))
+ return false;
+
+ /* ip options */
+ if (iph->ihl * 4 != sizeof(*iph))
+ return false;
+
+ if (iph->ttl <= 1)
+ return false;
+
+ return true;
+}
+
+static __always_inline bool
+xdp_flowtable_offload_check_tcp_state(void *ports, void *data_end, u8 proto)
+{
+ if (proto == IPPROTO_TCP) {
+ struct tcphdr *tcph = ports;
+
+ if (tcph + 1 > data_end)
+ return false;
+
+ if (tcph->fin || tcph->rst)
+ return false;
+ }
+
+ return true;
+}
+
+/* IP nat utility routines */
+
+static __always_inline void
+xdp_flowtable_offload_nat_port(struct flow_ports *ports, void *data_end,
+ u8 proto, __be16 port, __be16 nat_port)
+{
+ switch (proto) {
+ case IPPROTO_TCP: {
+ struct tcphdr *tcph = (struct tcphdr *)ports;
+
+ if (tcph + 1 > data_end)
+ break;
+
+ tcph->check = csum_replace4((__u32)tcph->check, (__u32)port,
+ (__u32)nat_port);
+ break;
+ }
+ case IPPROTO_UDP: {
+ struct udphdr *udph = (struct udphdr *)ports;
+
+ if (udph + 1 > data_end)
+ break;
+
+ if (!udph->check)
+ break;
+
+ udph->check = csum_replace4((__u32)udph->check, (__u32)port,
+ (__u32)nat_port);
+ if (!udph->check)
+ udph->check = CSUM_MANGLED_0;
+ break;
+ }
+ default:
+ break;
+ }
+}
+
+static __always_inline void
+xdp_flowtable_offload_snat_port(const struct flow_offload *flow,
+ struct flow_ports *ports, void *data_end,
+ u8 proto, enum flow_offload_tuple_dir dir)
+{
+ __be16 port, nat_port;
+
+ if (ports + 1 > data_end)
+ return;
+
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ port = ports->source;
+ bpf_core_read(&nat_port, bpf_core_type_size(nat_port),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port);
+ ports->source = nat_port;
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ port = ports->dest;
+ bpf_core_read(&nat_port, bpf_core_type_size(nat_port),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port);
+ ports->dest = nat_port;
+ break;
+ default:
+ return;
+ }
+
+ xdp_flowtable_offload_nat_port(ports, data_end, proto, port, nat_port);
+}
+
+static __always_inline void
+xdp_flowtable_offload_dnat_port(const struct flow_offload *flow,
+ struct flow_ports *ports, void *data_end,
+ u8 proto, enum flow_offload_tuple_dir dir)
+{
+ __be16 port, nat_port;
+
+ if (ports + 1 > data_end)
+ return;
+
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ port = ports->dest;
+ bpf_core_read(&nat_port, bpf_core_type_size(nat_port),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port);
+ ports->dest = nat_port;
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ port = ports->source;
+ bpf_core_read(&nat_port, bpf_core_type_size(nat_port),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port);
+ ports->source = nat_port;
+ break;
+ default:
+ return;
+ }
+
+ xdp_flowtable_offload_nat_port(ports, data_end, proto, port, nat_port);
+}
+
+static __always_inline void
+xdp_flowtable_offload_ip_l4(struct iphdr *iph, void *data_end,
+ __be32 addr, __be32 nat_addr)
+{
+ switch (iph->protocol) {
+ case IPPROTO_TCP: {
+ struct tcphdr *tcph = (struct tcphdr *)(iph + 1);
+
+ if (tcph + 1 > data_end)
+ break;
+
+ tcph->check = csum_replace4((__u32)tcph->check, addr,
+ nat_addr);
+ break;
+ }
+ case IPPROTO_UDP: {
+ struct udphdr *udph = (struct udphdr *)(iph + 1);
+
+ if (udph + 1 > data_end)
+ break;
+
+ if (!udph->check)
+ break;
+
+ udph->check = csum_replace4((__u32)udph->check, addr,
+ nat_addr);
+ if (!udph->check)
+ udph->check = CSUM_MANGLED_0;
+ break;
+ }
+ default:
+ break;
+ }
+}
+
+static __always_inline void
+xdp_flowtable_offload_snat_ip(const struct flow_offload *flow,
+ struct iphdr *iph, void *data_end,
+ enum flow_offload_tuple_dir dir)
+{
+ __be32 addr, nat_addr;
+
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ addr = iph->saddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v4.s_addr);
+ iph->saddr = nat_addr;
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ addr = iph->daddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v4.s_addr);
+ iph->daddr = nat_addr;
+ break;
+ default:
+ return;
+ }
+ iph->check = csum_replace4((__u32)iph->check, addr, nat_addr);
+
+ xdp_flowtable_offload_ip_l4(iph, data_end, addr, nat_addr);
+}
+
+static __always_inline void
+xdp_flowtable_offload_get_dnat_ip(const struct flow_offload *flow,
+ enum flow_offload_tuple_dir dir,
+ __be32 *addr)
+{
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ bpf_core_read(addr, sizeof(*addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v4.s_addr);
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ bpf_core_read(addr, sizeof(*addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v4.s_addr);
+ break;
+ }
+}
+
+static __always_inline void
+xdp_flowtable_offload_dnat_ip(const struct flow_offload *flow,
+ struct iphdr *iph, void *data_end,
+ enum flow_offload_tuple_dir dir)
+{
+ __be32 addr, nat_addr;
+
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ addr = iph->daddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v4.s_addr);
+ iph->daddr = nat_addr;
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ addr = iph->saddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v4.s_addr);
+ iph->saddr = nat_addr;
+ break;
+ default:
+ return;
+ }
+ iph->check = csum_replace4((__u32)iph->check, addr, nat_addr);
+
+ xdp_flowtable_offload_ip_l4(iph, data_end, addr, nat_addr);
+}
+
+static __always_inline void
+xdp_flowtable_offload_ipv6_l4(struct ipv6hdr *ip6h, void *data_end,
+ struct in6_addr *addr, struct in6_addr *nat_addr)
+{
+ switch (ip6h->nexthdr) {
+ case IPPROTO_TCP: {
+ struct tcphdr *tcph = (struct tcphdr *)(ip6h + 1);
+
+ if (tcph + 1 > data_end)
+ break;
+
+ tcph->check = csum_replace16((__u32)tcph->check,
+ addr->in6_u.u6_addr32,
+ nat_addr->in6_u.u6_addr32);
+ break;
+ }
+ case IPPROTO_UDP: {
+ struct udphdr *udph = (struct udphdr *)(ip6h + 1);
+
+ if (udph + 1 > data_end)
+ break;
+
+ if (!udph->check)
+ break;
+
+ udph->check = csum_replace16((__u32)udph->check,
+ addr->in6_u.u6_addr32,
+ nat_addr->in6_u.u6_addr32);
+ if (!udph->check)
+ udph->check = CSUM_MANGLED_0;
+ break;
+ }
+ default:
+ break;
+ }
+}
+
+static __always_inline void
+xdp_flowtable_offload_snat_ipv6(const struct flow_offload *flow,
+ struct ipv6hdr *ip6h, void *data_end,
+ enum flow_offload_tuple_dir dir)
+{
+ struct in6_addr addr, nat_addr;
+
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ addr = ip6h->saddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6);
+ ip6h->saddr = nat_addr;
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ addr = ip6h->daddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6);
+ ip6h->daddr = nat_addr;
+ break;
+ default:
+ return;
+ }
+
+ xdp_flowtable_offload_ipv6_l4(ip6h, data_end, &addr, &nat_addr);
+}
+
+static __always_inline void
+xdp_flowtable_offload_get_dnat_ipv6(const struct flow_offload *flow,
+ enum flow_offload_tuple_dir dir,
+ struct in6_addr *addr)
+{
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ bpf_core_read(addr, sizeof(*addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6);
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ bpf_core_read(addr, sizeof(*addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6);
+ break;
+ }
+}
+
+static __always_inline void
+xdp_flowtable_offload_dnat_ipv6(const struct flow_offload *flow,
+ struct ipv6hdr *ip6h, void *data_end,
+ enum flow_offload_tuple_dir dir)
+{
+ struct in6_addr addr, nat_addr;
+
+ switch (dir) {
+ case FLOW_OFFLOAD_DIR_ORIGINAL:
+ addr = ip6h->daddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6);
+ ip6h->daddr = nat_addr;
+ break;
+ case FLOW_OFFLOAD_DIR_REPLY:
+ addr = ip6h->saddr;
+ bpf_core_read(&nat_addr, bpf_core_type_size(nat_addr),
+ &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6);
+ ip6h->saddr = nat_addr;
+ break;
+ default:
+ return;
+ }
+
+ xdp_flowtable_offload_ipv6_l4(ip6h, data_end, &addr, &nat_addr);
+}
+
+static __always_inline void
+xdp_flowtable_offload_forward_ip(const struct flow_offload *flow,
+ void *data, void *data_end,
+ struct flow_ports *ports,
+ enum flow_offload_tuple_dir dir,
+ unsigned long flags)
+{
+ struct iphdr *iph = data + sizeof(struct ethhdr);
+
+ if (iph + 1 > data_end)
+ return;
+
+ if (flags & BIT(NF_FLOW_SNAT)) {
+ xdp_flowtable_offload_snat_port(flow, ports, data_end,
+ iph->protocol, dir);
+ xdp_flowtable_offload_snat_ip(flow, iph, data_end, dir);
+ }
+ if (flags & BIT(NF_FLOW_DNAT)) {
+ xdp_flowtable_offload_dnat_port(flow, ports, data_end,
+ iph->protocol, dir);
+ xdp_flowtable_offload_dnat_ip(flow, iph, data_end, dir);
+ }
+
+ ip_decrease_ttl(iph);
+}
+
+static __always_inline void
+xdp_flowtable_offload_forward_ipv6(const struct flow_offload *flow,
+ void *data, void *data_end,
+ struct flow_ports *ports,
+ enum flow_offload_tuple_dir dir,
+ unsigned long flags)
+{
+ struct ipv6hdr *ip6h = data + sizeof(struct ethhdr);
+
+ if (ip6h + 1 > data_end)
+ return;
+
+ if (flags & BIT(NF_FLOW_SNAT)) {
+ xdp_flowtable_offload_snat_port(flow, ports, data_end,
+ ip6h->nexthdr, dir);
+ xdp_flowtable_offload_snat_ipv6(flow, ip6h, data_end, dir);
+ }
+ if (flags & BIT(NF_FLOW_DNAT)) {
+ xdp_flowtable_offload_dnat_port(flow, ports, data_end,
+ ip6h->nexthdr, dir);
+ xdp_flowtable_offload_dnat_ipv6(flow, ip6h, data_end, dir);
+ }
+
+ ip6h->hop_limit--;
+}
+
+SEC("xdp")
+int xdp_flowtable_offload(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ struct flow_offload_tuple_rhash *tuplehash;
+ struct bpf_fib_lookup tuple = {
+ .ifindex = ctx->ingress_ifindex,
+ };
+ void *data = (void *)(long)ctx->data;
+ enum flow_offload_tuple_dir dir;
+ struct ethhdr *eth = data;
+ struct flow_offload *flow;
+ struct flow_ports *ports;
+ unsigned long flags;
+ int iifindex;
+
+ if (eth + 1 > data_end)
+ return XDP_PASS;
+
+ switch (eth->h_proto) {
+ case bpf_htons(ETH_P_IP): {
+ struct iphdr *iph = data + sizeof(*eth);
+
+ ports = (struct flow_ports *)(iph + 1);
+ if (ports + 1 > data_end)
+ return XDP_PASS;
+
+ /* sanity check on ip header */
+ if (!xdp_flowtable_offload_check_iphdr(iph))
+ return XDP_PASS;
+
+ if (!xdp_flowtable_offload_check_tcp_state(ports, data_end,
+ iph->protocol))
+ return XDP_PASS;
+
+ tuple.family = AF_INET;
+ tuple.tos = iph->tos;
+ tuple.l4_protocol = iph->protocol;
+ tuple.tot_len = bpf_ntohs(iph->tot_len);
+ tuple.ipv4_src = iph->saddr;
+ tuple.ipv4_dst = iph->daddr;
+ tuple.sport = ports->source;
+ tuple.dport = ports->dest;
+ break;
+ }
+ case bpf_htons(ETH_P_IPV6): {
+ struct in6_addr *src = (struct in6_addr *)tuple.ipv6_src;
+ struct in6_addr *dst = (struct in6_addr *)tuple.ipv6_dst;
+ struct ipv6hdr *ip6h = data + sizeof(*eth);
+
+ ports = (struct flow_ports *)(ip6h + 1);
+ if (ports + 1 > data_end)
+ return XDP_PASS;
+
+ if (ip6h->hop_limit <= 1)
+ return XDP_PASS;
+
+ if (!xdp_flowtable_offload_check_tcp_state(ports, data_end,
+ ip6h->nexthdr))
+ return XDP_PASS;
+
+ tuple.family = AF_INET6;
+ tuple.l4_protocol = ip6h->nexthdr;
+ tuple.tot_len = bpf_ntohs(ip6h->payload_len);
+ *src = ip6h->saddr;
+ *dst = ip6h->daddr;
+ tuple.sport = ports->source;
+ tuple.dport = ports->dest;
+ break;
+ }
+ default:
+ return XDP_PASS;
+ }
+
+ tuplehash = bpf_xdp_flow_offload_lookup(ctx, &tuple, sizeof(tuple));
+ if (IS_ERR_VALUE(tuplehash))
+ return XDP_PASS;
+
+ dir = tuplehash->tuple.dir;
+ flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
+ if (bpf_core_read(&flags, sizeof(flags), &flow->flags))
+ return XDP_PASS;
+
+ switch (tuplehash->tuple.xmit_type) {
+ case FLOW_OFFLOAD_XMIT_NEIGH:
+ /* update the destination address in case of dnatting before
+ * performing the route lookup
+ */
+ if (tuple.family == AF_INET6)
+ xdp_flowtable_offload_get_dnat_ipv6(flow, dir,
+ (struct in6_addr *)&tuple.ipv6_dst);
+ else
+ xdp_flowtable_offload_get_dnat_ip(flow, dir, &tuple.ipv4_src);
+
+ if (bpf_fib_lookup(ctx, &tuple, sizeof(tuple), 0))
+ return XDP_PASS;
+
+ if (tuple.family == AF_INET6)
+ xdp_flowtable_offload_forward_ipv6(flow, data, data_end,
+ ports, dir, flags);
+ else
+ xdp_flowtable_offload_forward_ip(flow, data, data_end,
+ ports, dir, flags);
+
+ __builtin_memcpy(eth->h_dest, tuple.dmac, ETH_ALEN);
+ __builtin_memcpy(eth->h_source, tuple.smac, ETH_ALEN);
+ iifindex = tuple.ifindex;
+ break;
+ case FLOW_OFFLOAD_XMIT_DIRECT:
+ default:
+ return XDP_PASS;
+ }
+
+ return bpf_redirect(iifindex, 0);
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/xdp_flowtable_offload_user.c b/samples/bpf/xdp_flowtable_offload_user.c
new file mode 100644
index 0000000000000..179b1f34b48fd
--- /dev/null
+++ b/samples/bpf/xdp_flowtable_offload_user.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2024 Lorenzo Bianconi <lorenzo@...nel.org>
+ */
+static const char *__doc__ =
+"XDP flowtable integration example\n"
+"Usage: xdp_flowtable_offload <IFINDEX|IFNAME>\n";
+
+#include <linux/bpf.h>
+#include <linux/if_link.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <net/if.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <getopt.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include "bpf_util.h"
+#include "xdp_sample_user.h"
+#include "xdp_flowtable_offload.skel.h"
+
+static int mask = SAMPLE_RX_CNT | SAMPLE_EXCEPTION_CNT;
+
+DEFINE_SAMPLE_INIT(xdp_flowtable_offload);
+
+static const struct option long_options[] = {
+ { "help", no_argument, NULL, 'h' },
+ { "generic", no_argument, NULL, 'g' },
+ {}
+};
+
+int main(int argc, char **argv)
+{
+ struct xdp_flowtable_offload *skel;
+ int ret = EXIT_FAIL_OPTION;
+ char ifname[IF_NAMESIZE];
+ bool generic = false;
+ int ifindex;
+ int opt;
+
+ while ((opt = getopt_long(argc, argv, "hg",
+ long_options, NULL)) != -1) {
+ switch (opt) {
+ case 'g':
+ generic = true;
+ break;
+ case 'h':
+ default:
+ sample_usage(argv, long_options, __doc__, mask, false);
+ return ret;
+ }
+ }
+
+ if (argc <= optind) {
+ sample_usage(argv, long_options, __doc__, mask, true);
+ goto end;
+ }
+
+ ifindex = if_nametoindex(argv[optind]);
+ if (!ifindex)
+ ifindex = strtoul(argv[optind], NULL, 0);
+
+ if (!ifindex) {
+ fprintf(stderr, "Bad interface index or name\n");
+ sample_usage(argv, long_options, __doc__, mask, true);
+ goto end;
+ }
+
+ skel = xdp_flowtable_offload__open();
+ if (!skel) {
+ fprintf(stderr, "Failed to xdp_flowtable_offload__open: %s\n",
+ strerror(errno));
+ ret = EXIT_FAIL_BPF;
+ goto end;
+ }
+
+ ret = sample_init_pre_load(skel);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to sample_init_pre_load: %s\n", strerror(-ret));
+ ret = EXIT_FAIL_BPF;
+ goto end_destroy;
+ }
+
+ ret = xdp_flowtable_offload__load(skel);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to xdp_flowtable_offload__load: %s\n",
+ strerror(errno));
+ ret = EXIT_FAIL_BPF;
+ goto end_destroy;
+ }
+
+ ret = sample_init(skel, mask);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to initialize sample: %s\n", strerror(-ret));
+ ret = EXIT_FAIL;
+ goto end_destroy;
+ }
+
+ if (sample_install_xdp(skel->progs.xdp_flowtable_offload,
+ ifindex, generic, false) < 0) {
+ ret = EXIT_FAIL_XDP;
+ goto end_destroy;
+ }
+
+ ret = EXIT_FAIL;
+ if (!if_indextoname(ifindex, ifname)) {
+ fprintf(stderr, "Failed to if_indextoname for %d: %s\n", ifindex,
+ strerror(errno));
+ goto end_destroy;
+ }
+
+ ret = sample_run(2, NULL, NULL);
+ if (ret < 0) {
+ fprintf(stderr, "Failed during sample run: %s\n", strerror(-ret));
+ ret = EXIT_FAIL;
+ goto end_destroy;
+ }
+ ret = EXIT_OK;
+end_destroy:
+ xdp_flowtable_offload__destroy(skel);
+end:
+ sample_exit(ret);
+}
--
2.45.0
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