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samples: bpf: add skb->field examples and tests 

- modify sockex1 example to count number of bytes in outgoing packets
- modify sockex2 example to count number of bytes and packets per flow
- add 4 stress tests that exercise 'skb->field' code path of verifier

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexei Starovoitov 2015-03-13 11:57:43 -07:00 committed by David S. Miller
parent 9bac3d6d54
commit 614cd3bd37
5 changed files with 101 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
samples/bpf/sockex1_kern.c
View File

@ -1,5 +1,6 @@
#include <uapi/linux/bpf.h> #include <uapi/linux/bpf.h>
#include <uapi/linux/if_ether.h> #include <uapi/linux/if_ether.h>
#include <uapi/linux/if_packet.h>
#include <uapi/linux/ip.h> #include <uapi/linux/ip.h>
#include "bpf_helpers.h" #include "bpf_helpers.h"
@ -11,14 +12,17 @@ struct bpf_map_def SEC("maps") my_map = {
}; };
SEC("socket1") SEC("socket1")
int bpf_prog1(struct sk_buff *skb) int bpf_prog1(struct __sk_buff *skb)
{ {
int index = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)); int index = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol));
long *value; long *value;
if (skb->pkt_type != PACKET_OUTGOING)
return 0;
value = bpf_map_lookup_elem(&my_map, &index); value = bpf_map_lookup_elem(&my_map, &index);
if (value) if (value)
__sync_fetch_and_add(value, 1); __sync_fetch_and_add(value, skb->len);
return 0; return 0;
} }

2
samples/bpf/sockex1_user.c
View File

@ -40,7 +40,7 @@ int main(int ac, char **argv)
key = IPPROTO_ICMP; key = IPPROTO_ICMP;
assert(bpf_lookup_elem(map_fd[0], &key, &icmp_cnt) == 0); assert(bpf_lookup_elem(map_fd[0], &key, &icmp_cnt) == 0);
printf("TCP %lld UDP %lld ICMP %lld packets\n", printf("TCP %lld UDP %lld ICMP %lld bytes\n",
tcp_cnt, udp_cnt, icmp_cnt); tcp_cnt, udp_cnt, icmp_cnt);
sleep(1); sleep(1);
} }

26
samples/bpf/sockex2_kern.c
View File

@ -42,13 +42,13 @@ static inline int proto_ports_offset(__u64 proto)
} }
} }
static inline int ip_is_fragment(struct sk_buff *ctx, __u64 nhoff) static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
{ {
return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off)) return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
& (IP_MF | IP_OFFSET); & (IP_MF | IP_OFFSET);
} }
static inline __u32 ipv6_addr_hash(struct sk_buff *ctx, __u64 off) static inline __u32 ipv6_addr_hash(struct __sk_buff *ctx, __u64 off)
{ {
__u64 w0 = load_word(ctx, off); __u64 w0 = load_word(ctx, off);
__u64 w1 = load_word(ctx, off + 4); __u64 w1 = load_word(ctx, off + 4);
@ -58,7 +58,7 @@ static inline __u32 ipv6_addr_hash(struct sk_buff *ctx, __u64 off)
return (__u32)(w0 ^ w1 ^ w2 ^ w3); return (__u32)(w0 ^ w1 ^ w2 ^ w3);
} }
static inline __u64 parse_ip(struct sk_buff *skb, __u64 nhoff, __u64 *ip_proto, static inline __u64 parse_ip(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
struct flow_keys *flow) struct flow_keys *flow)
{ {
__u64 verlen; __u64 verlen;
@ -82,7 +82,7 @@ static inline __u64 parse_ip(struct sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
return nhoff; return nhoff;
} }
static inline __u64 parse_ipv6(struct sk_buff *skb, __u64 nhoff, __u64 *ip_proto, static inline __u64 parse_ipv6(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
struct flow_keys *flow) struct flow_keys *flow)
{ {
*ip_proto = load_byte(skb, *ip_proto = load_byte(skb,
@ -96,7 +96,7 @@ static inline __u64 parse_ipv6(struct sk_buff *skb, __u64 nhoff, __u64 *ip_proto
return nhoff; return nhoff;
} }
static inline bool flow_dissector(struct sk_buff *skb, struct flow_keys *flow) static inline bool flow_dissector(struct __sk_buff *skb, struct flow_keys *flow)
{ {
__u64 nhoff = ETH_HLEN; __u64 nhoff = ETH_HLEN;
__u64 ip_proto; __u64 ip_proto;
@ -183,18 +183,23 @@ static inline bool flow_dissector(struct sk_buff *skb, struct flow_keys *flow)
return true; return true;
} }
struct pair {
long packets;
long bytes;
};
struct bpf_map_def SEC("maps") hash_map = { struct bpf_map_def SEC("maps") hash_map = {
.type = BPF_MAP_TYPE_HASH, .type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(__be32), .key_size = sizeof(__be32),
.value_size = sizeof(long), .value_size = sizeof(struct pair),
.max_entries = 1024, .max_entries = 1024,
}; };
SEC("socket2") SEC("socket2")
int bpf_prog2(struct sk_buff *skb) int bpf_prog2(struct __sk_buff *skb)
{ {
struct flow_keys flow; struct flow_keys flow;
long *value; struct pair *value;
u32 key; u32 key;
if (!flow_dissector(skb, &flow)) if (!flow_dissector(skb, &flow))
@ -203,9 +208,10 @@ int bpf_prog2(struct sk_buff *skb)
key = flow.dst; key = flow.dst;
value = bpf_map_lookup_elem(&hash_map, &key); value = bpf_map_lookup_elem(&hash_map, &key);
if (value) { if (value) {
__sync_fetch_and_add(value, 1); __sync_fetch_and_add(&value->packets, 1);
__sync_fetch_and_add(&value->bytes, skb->len);
} else { } else {
long val = 1; struct pair val = {1, skb->len};
bpf_map_update_elem(&hash_map, &key, &val, BPF_ANY); bpf_map_update_elem(&hash_map, &key, &val, BPF_ANY);
} }

11
samples/bpf/sockex2_user.c
View File

@ -6,6 +6,11 @@
#include <unistd.h> #include <unistd.h>
#include <arpa/inet.h> #include <arpa/inet.h>
struct pair {
__u64 packets;
__u64 bytes;
};
int main(int ac, char **argv) int main(int ac, char **argv)
{ {
char filename[256]; char filename[256];
@ -29,13 +34,13 @@ int main(int ac, char **argv)
for (i = 0; i < 5; i++) { for (i = 0; i < 5; i++) {
int key = 0, next_key; int key = 0, next_key;
long long value; struct pair value;
while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) { while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) {
bpf_lookup_elem(map_fd[0], &next_key, &value); bpf_lookup_elem(map_fd[0], &next_key, &value);
printf("ip %s count %lld\n", printf("ip %s bytes %lld packets %lld\n",
inet_ntoa((struct in_addr){htonl(next_key)}), inet_ntoa((struct in_addr){htonl(next_key)}),
value); value.bytes, value.packets);
key = next_key; key = next_key;
} }
sleep(1); sleep(1);

70
samples/bpf/test_verifier.c
View File

@ -14,6 +14,7 @@
#include <linux/unistd.h> #include <linux/unistd.h>
#include <string.h> #include <string.h>
#include <linux/filter.h> #include <linux/filter.h>
#include <stddef.h>
#include "libbpf.h" #include "libbpf.h"
#define MAX_INSNS 512 #define MAX_INSNS 512
@ -642,6 +643,75 @@ static struct bpf_test tests[] = {
}, },
.result = ACCEPT, .result = ACCEPT,
}, },
{
"access skb fields ok",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, len)),
BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, pkt_type)),
BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, queue_mapping)),
BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
},
{
"access skb fields bad1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -4),
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
.result = REJECT,
},
{
"access skb fields bad2",
.insns = {
BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 0, 9),
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, pkt_type)),
BPF_EXIT_INSN(),
},
.fixup = {4},
.errstr = "different pointers",
.result = REJECT,
},
{
"access skb fields bad3",
.insns = {
BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 0, 2),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, pkt_type)),
BPF_EXIT_INSN(),
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_JMP_IMM(BPF_JA, 0, 0, -12),
},
.fixup = {6},
.errstr = "different pointers",
.result = REJECT,
},
}; };
static int probe_filter_length(struct bpf_insn *fp) static int probe_filter_length(struct bpf_insn *fp)