From ae173a915785e55574c1fc54edf58b9b87b28c22 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Thu, 25 Jul 2019 15:52:29 -0700 Subject: [PATCH] selftests/bpf: support BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG 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 Acked-by: Willem de Bruijn Acked-by: Song Liu Cc: Song Liu Cc: Willem de Bruijn Cc: Petar Penkov Signed-off-by: Stanislav Fomichev Signed-off-by: Alexei Starovoitov --- .../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 c938283..8e8c18a 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 #include +#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 5ae485a..f931cd3 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); } -- 2.7.4