bpf_flow.c: exit early unless BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG is
passed in flags. Also, set ip_proto earlier, this makes sure we have
correct value with fragmented packets.
Add selftest cases to test ipv4/ipv6 fragments and skip eth_get_headlen
tests that don't have BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG flag.
eth_get_headlen calls flow dissector with
BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG flag so we can't run tests that
have different set of input flags against it.
v2:
* sefltests -> selftests (Willem de Bruijn)
* Reword a comment about eth_get_headlen flags (Song Liu)
Acked-by: Petar Penkov <ppenkov@xxxxxxxxxx>
Acked-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Cc: Petar Penkov <ppenkov@xxxxxxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
.../selftests/bpf/prog_tests/flow_dissector.c | 133 +++++++++++++++++-
tools/testing/selftests/bpf/progs/bpf_flow.c | 29 +++-
2 files changed, 155 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
index c938283ac232..8e8c18aced9b 100644
--- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
+++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
@@ -5,6 +5,10 @@
#include <linux/if_tun.h>
#include <sys/uio.h>
+#ifndef IP_MF
+#define IP_MF 0x2000
+#endif
+
#define CHECK_FLOW_KEYS(desc, got, expected) \
CHECK_ATTR(memcmp(&got, &expected, sizeof(got)) != 0, \
desc, \
@@ -49,6 +53,18 @@ struct ipv6_pkt {
struct tcphdr tcp;
} __packed;
+struct ipv6_frag_pkt {
+ struct ethhdr eth;
+ struct ipv6hdr iph;
+ struct frag_hdr {
+ __u8 nexthdr;
+ __u8 reserved;
+ __be16 frag_off;
+ __be32 identification;
+ } ipf;
+ struct tcphdr tcp;
+} __packed;
+
struct dvlan_ipv6_pkt {
struct ethhdr eth;
__u16 vlan_tci;
@@ -65,9 +81,11 @@ struct test {
struct ipv4_pkt ipv4;
struct svlan_ipv4_pkt svlan_ipv4;
struct ipv6_pkt ipv6;
+ struct ipv6_frag_pkt ipv6_frag;
struct dvlan_ipv6_pkt dvlan_ipv6;
} pkt;
struct bpf_flow_keys keys;
+ __u32 flags;
};
#define VLAN_HLEN 4
@@ -143,6 +161,102 @@ struct test tests[] = {
.n_proto = __bpf_constant_htons(ETH_P_IPV6),
},
},
+ {
+ .name = "ipv4-frag",
+ .pkt.ipv4 = {
+ .eth.h_proto = __bpf_constant_htons(ETH_P_IP),
+ .iph.ihl = 5,
+ .iph.protocol = IPPROTO_TCP,
+ .iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
+ .iph.frag_off = __bpf_constant_htons(IP_MF),
+ .tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
+ },
+ .keys = {
+ .flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
+ .nhoff = ETH_HLEN,
+ .thoff = ETH_HLEN + sizeof(struct iphdr),
+ .addr_proto = ETH_P_IP,
+ .ip_proto = IPPROTO_TCP,
+ .n_proto = __bpf_constant_htons(ETH_P_IP),
+ .is_frag = true,
+ .is_first_frag = true,
+ .sport = 80,
+ .dport = 8080,
+ },
+ .flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
+ },
+ {
+ .name = "ipv4-no-frag",
+ .pkt.ipv4 = {
+ .eth.h_proto = __bpf_constant_htons(ETH_P_IP),
+ .iph.ihl = 5,
+ .iph.protocol = IPPROTO_TCP,
+ .iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
+ .iph.frag_off = __bpf_constant_htons(IP_MF),
+ .tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
+ },
+ .keys = {
+ .nhoff = ETH_HLEN,
+ .thoff = ETH_HLEN + sizeof(struct iphdr),
+ .addr_proto = ETH_P_IP,
+ .ip_proto = IPPROTO_TCP,
+ .n_proto = __bpf_constant_htons(ETH_P_IP),
+ .is_frag = true,
+ .is_first_frag = true,
+ },
+ },
+ {
+ .name = "ipv6-frag",
+ .pkt.ipv6_frag = {
+ .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .iph.nexthdr = IPPROTO_FRAGMENT,
+ .iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
+ .ipf.nexthdr = IPPROTO_TCP,
+ .tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
+ },
+ .keys = {
+ .flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
+ .nhoff = ETH_HLEN,
+ .thoff = ETH_HLEN + sizeof(struct ipv6hdr) +
+ sizeof(struct frag_hdr),
+ .addr_proto = ETH_P_IPV6,
+ .ip_proto = IPPROTO_TCP,
+ .n_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .is_frag = true,
+ .is_first_frag = true,
+ .sport = 80,
+ .dport = 8080,
+ },
+ .flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
+ },
+ {
+ .name = "ipv6-no-frag",
+ .pkt.ipv6_frag = {
+ .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .iph.nexthdr = IPPROTO_FRAGMENT,
+ .iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
+ .ipf.nexthdr = IPPROTO_TCP,
+ .tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
+ },
+ .keys = {
+ .nhoff = ETH_HLEN,
+ .thoff = ETH_HLEN + sizeof(struct ipv6hdr) +
+ sizeof(struct frag_hdr),
+ .addr_proto = ETH_P_IPV6,
+ .ip_proto = IPPROTO_TCP,
+ .n_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .is_frag = true,
+ .is_first_frag = true,
+ },
+ },
};
static int create_tap(const char *ifname)
@@ -225,6 +339,13 @@ void test_flow_dissector(void)
.data_size_in = sizeof(tests[i].pkt),
.data_out = &flow_keys,
};
+ static struct bpf_flow_keys ctx = {};
+
+ if (tests[i].flags) {
+ tattr.ctx_in = &ctx;
+ tattr.ctx_size_in = sizeof(ctx);
+ ctx.flags = tests[i].flags;
+ }
err = bpf_prog_test_run_xattr(&tattr);
CHECK_ATTR(tattr.data_size_out != sizeof(flow_keys) ||
@@ -251,10 +372,20 @@ void test_flow_dissector(void)
CHECK(err, "ifup", "err %d errno %d\n", err, errno);
for (i = 0; i < ARRAY_SIZE(tests); i++) {
- struct bpf_flow_keys flow_keys = {};
+ /* Keep in sync with 'flags' from eth_get_headlen. */
+ __u32 eth_get_headlen_flags =
+ BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
struct bpf_prog_test_run_attr tattr = {};
+ struct bpf_flow_keys flow_keys = {};
__u32 key = 0;
+ /* For skb-less case we can't pass input flags; run
+ * only the tests that have a matching set of flags.
+ */
+
+ if (tests[i].flags != eth_get_headlen_flags)
+ continue;
+
err = tx_tap(tap_fd, &tests[i].pkt, sizeof(tests[i].pkt));
CHECK(err < 0, "tx_tap", "err %d errno %d\n", err, errno);
diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c
index 5ae485a6af3f..f931cd3db9d4 100644
--- a/tools/testing/selftests/bpf/progs/bpf_flow.c
+++ b/tools/testing/selftests/bpf/progs/bpf_flow.c
@@ -153,7 +153,6 @@ static __always_inline int parse_ip_proto(struct __sk_buff *skb, __u8 proto)
struct tcphdr *tcp, _tcp;
struct udphdr *udp, _udp;
- keys->ip_proto = proto;
switch (proto) {
case IPPROTO_ICMP:
icmp = bpf_flow_dissect_get_header(skb, sizeof(*icmp), &_icmp);
@@ -231,7 +230,6 @@ static __always_inline int parse_ipv6_proto(struct __sk_buff *skb, __u8 nexthdr)
{
struct bpf_flow_keys *keys = skb->flow_keys;
- keys->ip_proto = nexthdr;
switch (nexthdr) {
case IPPROTO_HOPOPTS:
case IPPROTO_DSTOPTS:
@@ -266,6 +264,7 @@ PROG(IP)(struct __sk_buff *skb)
keys->addr_proto = ETH_P_IP;
keys->ipv4_src = iph->saddr;
keys->ipv4_dst = iph->daddr;
+ keys->ip_proto = iph->protocol;
keys->thoff += iph->ihl << 2;
if (data + keys->thoff > data_end)
@@ -273,13 +272,20 @@ PROG(IP)(struct __sk_buff *skb)
if (iph->frag_off & bpf_htons(IP_MF | IP_OFFSET)) {
keys->is_frag = true;
- if (iph->frag_off & bpf_htons(IP_OFFSET))
+ if (iph->frag_off & bpf_htons(IP_OFFSET)) {
/* From second fragment on, packets do not have headers
* we can parse.
*/
done = true;
- else
+ } else {
keys->is_first_frag = true;
+ /* No need to parse fragmented packet unless
+ * explicitly asked for.
+ */
+ if (!(keys->flags &
+ BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
+ done = true;
+ }
}
if (done)
@@ -301,6 +307,7 @@ PROG(IPV6)(struct __sk_buff *skb)
memcpy(&keys->ipv6_src, &ip6h->saddr, 2*sizeof(ip6h->saddr));
keys->thoff += sizeof(struct ipv6hdr);
+ keys->ip_proto = ip6h->nexthdr;
return parse_ipv6_proto(skb, ip6h->nexthdr);
}
@@ -317,7 +324,8 @@ PROG(IPV6OP)(struct __sk_buff *skb)
/* hlen is in 8-octets and does not include the first 8 bytes
* of the header
*/
- skb->flow_keys->thoff += (1 + ip6h->hdrlen) << 3;
+ keys->thoff += (1 + ip6h->hdrlen) << 3;
+ keys->ip_proto = ip6h->nexthdr;
return parse_ipv6_proto(skb, ip6h->nexthdr);
}
@@ -333,9 +341,18 @@ PROG(IPV6FR)(struct __sk_buff *skb)
keys->thoff += sizeof(*fragh);
keys->is_frag = true;
- if (!(fragh->frag_off & bpf_htons(IP6_OFFSET)))
+ keys->ip_proto = fragh->nexthdr;
+
+ if (!(fragh->frag_off & bpf_htons(IP6_OFFSET))) {
keys->is_first_frag = true;
+ /* No need to parse fragmented packet unless
+ * explicitly asked for.
+ */
+ if (!(keys->flags & BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
+ return export_flow_keys(keys, BPF_OK);
+ }
+
return parse_ipv6_proto(skb, fragh->nexthdr);
}
--
2.22.0.709.g102302147b-goog
