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Message-Id: <1442368295-5204-2-git-send-email-ast@plumgrid.com>
Date: Tue, 15 Sep 2015 18:51:34 -0700
From: Alexei Starovoitov <ast@...mgrid.com>
To: "David S. Miller" <davem@...emloft.net>
Cc: Jamal Hadi Salim <jhs@...atatu.com>,
Daniel Borkmann <daniel@...earbox.net>, netdev@...r.kernel.org
Subject: [PATCH net-next 1/2] cls_bpf: introduce integrated actions
From: Daniel Borkmann <daniel@...earbox.net>
Often cls_bpf classifier is used with single action drop attached.
Optimize this use case and let cls_bpf return both classid and action.
For backwards compatibility reasons enable this feature under
TCA_BPF_FLAG_ACT_DIRECT flag.
Then more interesting programs like the following are easier to write:
int cls_bpf_prog(struct __sk_buff *skb)
{
/* classify arp, ip, ipv6 into different traffic classes
* and drop all other packets
*/
switch (skb->protocol) {
case htons(ETH_P_ARP):
skb->tc_classid = 1;
break;
case htons(ETH_P_IP):
skb->tc_classid = 2;
break;
case htons(ETH_P_IPV6):
skb->tc_classid = 3;
break;
default:
return TC_ACT_SHOT;
}
return TC_ACT_OK;
}
Joint work with Daniel Borkmann.
Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Signed-off-by: Alexei Starovoitov <ast@...mgrid.com>
---
include/net/sch_generic.h | 2 +-
include/uapi/linux/bpf.h | 1 +
include/uapi/linux/pkt_cls.h | 3 +++
net/core/filter.c | 14 ++++++++++
net/sched/cls_bpf.c | 60 ++++++++++++++++++++++++++++++++++--------
5 files changed, 68 insertions(+), 12 deletions(-)
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 444faa89a55f..da61febb9091 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -251,7 +251,7 @@ struct tcf_proto {
struct qdisc_skb_cb {
unsigned int pkt_len;
u16 slave_dev_queue_mapping;
- u16 _pad;
+ u16 tc_classid;
#define QDISC_CB_PRIV_LEN 20
unsigned char data[QDISC_CB_PRIV_LEN];
};
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 92a48e2d5461..2fbd1c71fa3b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -293,6 +293,7 @@ struct __sk_buff {
__u32 tc_index;
__u32 cb[5];
__u32 hash;
+ __u32 tc_classid;
};
struct bpf_tunnel_key {
diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
index 4f0d1bc3647d..0a262a83f9d4 100644
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h
@@ -373,6 +373,8 @@ enum {
/* BPF classifier */
+#define TCA_BPF_FLAG_ACT_DIRECT (1 << 0)
+
enum {
TCA_BPF_UNSPEC,
TCA_BPF_ACT,
@@ -382,6 +384,7 @@ enum {
TCA_BPF_OPS,
TCA_BPF_FD,
TCA_BPF_NAME,
+ TCA_BPF_FLAGS,
__TCA_BPF_MAX,
};
diff --git a/net/core/filter.c b/net/core/filter.c
index 13079f03902e..971d6ba89758 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1632,6 +1632,9 @@ static bool __is_valid_access(int off, int size, enum bpf_access_type type)
static bool sk_filter_is_valid_access(int off, int size,
enum bpf_access_type type)
{
+ if (off == offsetof(struct __sk_buff, tc_classid))
+ return false;
+
if (type == BPF_WRITE) {
switch (off) {
case offsetof(struct __sk_buff, cb[0]) ...
@@ -1648,6 +1651,9 @@ static bool sk_filter_is_valid_access(int off, int size,
static bool tc_cls_act_is_valid_access(int off, int size,
enum bpf_access_type type)
{
+ if (off == offsetof(struct __sk_buff, tc_classid))
+ return type == BPF_WRITE ? true : false;
+
if (type == BPF_WRITE) {
switch (off) {
case offsetof(struct __sk_buff, mark):
@@ -1760,6 +1766,14 @@ static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,
*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, ctx_off);
break;
+ case offsetof(struct __sk_buff, tc_classid):
+ ctx_off -= offsetof(struct __sk_buff, tc_classid);
+ ctx_off += offsetof(struct sk_buff, cb);
+ ctx_off += offsetof(struct qdisc_skb_cb, tc_classid);
+ WARN_ON(type != BPF_WRITE);
+ *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, ctx_off);
+ break;
+
case offsetof(struct __sk_buff, tc_index):
#ifdef CONFIG_NET_SCHED
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, tc_index) != 2);
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index e5168f8b9640..77b0ef148256 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -38,6 +38,7 @@ struct cls_bpf_prog {
struct bpf_prog *filter;
struct list_head link;
struct tcf_result res;
+ bool exts_integrated;
struct tcf_exts exts;
u32 handle;
union {
@@ -52,6 +53,7 @@ struct cls_bpf_prog {
static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
[TCA_BPF_CLASSID] = { .type = NLA_U32 },
+ [TCA_BPF_FLAGS] = { .type = NLA_U32 },
[TCA_BPF_FD] = { .type = NLA_U32 },
[TCA_BPF_NAME] = { .type = NLA_NUL_STRING, .len = CLS_BPF_NAME_LEN },
[TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
@@ -59,6 +61,22 @@ static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
.len = sizeof(struct sock_filter) * BPF_MAXINSNS },
};
+static int cls_bpf_exec_opcode(int code)
+{
+ switch (code) {
+ case TC_ACT_OK:
+ case TC_ACT_RECLASSIFY:
+ case TC_ACT_SHOT:
+ case TC_ACT_PIPE:
+ case TC_ACT_STOLEN:
+ case TC_ACT_QUEUED:
+ case TC_ACT_UNSPEC:
+ return code;
+ default:
+ return TC_ACT_UNSPEC;
+ }
+}
+
static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
@@ -79,6 +97,8 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
list_for_each_entry_rcu(prog, &head->plist, link) {
int filter_res;
+ qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
+
if (at_ingress) {
/* It is safe to push/pull even if skb_shared() */
__skb_push(skb, skb->mac_len);
@@ -88,6 +108,16 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
filter_res = BPF_PROG_RUN(prog->filter, skb);
}
+ if (prog->exts_integrated) {
+ res->class = prog->res.class;
+ res->classid = qdisc_skb_cb(skb)->tc_classid;
+
+ ret = cls_bpf_exec_opcode(filter_res);
+ if (ret == TC_ACT_UNSPEC)
+ continue;
+ break;
+ }
+
if (filter_res == 0)
continue;
@@ -195,8 +225,7 @@ static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
return ret;
}
-static int cls_bpf_prog_from_ops(struct nlattr **tb,
- struct cls_bpf_prog *prog, u32 classid)
+static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
{
struct sock_filter *bpf_ops;
struct sock_fprog_kern fprog_tmp;
@@ -230,15 +259,13 @@ static int cls_bpf_prog_from_ops(struct nlattr **tb,
prog->bpf_ops = bpf_ops;
prog->bpf_num_ops = bpf_num_ops;
prog->bpf_name = NULL;
-
prog->filter = fp;
- prog->res.classid = classid;
return 0;
}
-static int cls_bpf_prog_from_efd(struct nlattr **tb,
- struct cls_bpf_prog *prog, u32 classid)
+static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
+ const struct tcf_proto *tp)
{
struct bpf_prog *fp;
char *name = NULL;
@@ -268,9 +295,7 @@ static int cls_bpf_prog_from_efd(struct nlattr **tb,
prog->bpf_ops = NULL;
prog->bpf_fd = bpf_fd;
prog->bpf_name = name;
-
prog->filter = fp;
- prog->res.classid = classid;
return 0;
}
@@ -280,8 +305,8 @@ static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
unsigned long base, struct nlattr **tb,
struct nlattr *est, bool ovr)
{
+ bool is_bpf, is_ebpf, have_exts = false;
struct tcf_exts exts;
- bool is_bpf, is_ebpf;
u32 classid;
int ret;
@@ -298,9 +323,22 @@ static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
return ret;
classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
+ if (tb[TCA_BPF_FLAGS]) {
+ u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
+
+ if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
+ tcf_exts_destroy(&exts);
+ return -EINVAL;
+ }
+
+ have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
+ }
+
+ prog->res.classid = classid;
+ prog->exts_integrated = have_exts;
- ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) :
- cls_bpf_prog_from_efd(tb, prog, classid);
+ ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
+ cls_bpf_prog_from_efd(tb, prog, tp);
if (ret < 0) {
tcf_exts_destroy(&exts);
return ret;
--
1.7.9.5
--
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