1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2024 Meta
3
4 #include "vmlinux.h"
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_core_read.h>
7 #include <bpf/bpf_endian.h>
8 #include "bpf_tracing_net.h"
9 #include "bpf_kfuncs.h"
10
11 #define ATTR __always_inline
12 #include "test_jhash.h"
13
ipv6_addr_loopback(const struct in6_addr * a)14 static bool ipv6_addr_loopback(const struct in6_addr *a)
15 {
16 return (a->s6_addr32[0] | a->s6_addr32[1] |
17 a->s6_addr32[2] | (a->s6_addr32[3] ^ bpf_htonl(1))) == 0;
18 }
19
ipv4_addr_loopback(__be32 a)20 static bool ipv4_addr_loopback(__be32 a)
21 {
22 return a == bpf_ntohl(0x7f000001);
23 }
24
25 volatile const unsigned int sf;
26 volatile const unsigned int ss;
27 volatile const __u16 ports[2];
28 unsigned int bucket[2];
29
30 SEC("iter/tcp")
iter_tcp_soreuse(struct bpf_iter__tcp * ctx)31 int iter_tcp_soreuse(struct bpf_iter__tcp *ctx)
32 {
33 struct sock *sk = (struct sock *)ctx->sk_common;
34 struct inet_hashinfo *hinfo;
35 unsigned int hash;
36 __u64 sock_cookie;
37 struct net *net;
38 int idx;
39
40 if (!sk)
41 return 0;
42
43 sock_cookie = bpf_get_socket_cookie(sk);
44 sk = bpf_core_cast(sk, struct sock);
45 if (sk->sk_family != sf ||
46 (ss && sk->sk_state != ss) ||
47 (sk->sk_family == AF_INET6 ?
48 !ipv6_addr_loopback(&sk->sk_v6_rcv_saddr) :
49 !ipv4_addr_loopback(sk->sk_rcv_saddr)))
50 return 0;
51
52 if (sk->sk_num == ports[0])
53 idx = 0;
54 else if (sk->sk_num == ports[1])
55 idx = 1;
56 else if (!ports[0] && !ports[1])
57 idx = 0;
58 else
59 return 0;
60
61 /* bucket selection as in inet_lhash2_bucket_sk() */
62 net = sk->sk_net.net;
63 hash = jhash2(sk->sk_v6_rcv_saddr.s6_addr32, 4, net->hash_mix);
64 hash ^= sk->sk_num;
65 hinfo = net->ipv4.tcp_death_row.hashinfo;
66 bucket[idx] = hash & hinfo->lhash2_mask;
67 bpf_seq_write(ctx->meta->seq, &idx, sizeof(idx));
68 bpf_seq_write(ctx->meta->seq, &sock_cookie, sizeof(sock_cookie));
69
70 return 0;
71 }
72
73 volatile const __u64 destroy_cookie;
74
75 SEC("iter/tcp")
iter_tcp_destroy(struct bpf_iter__tcp * ctx)76 int iter_tcp_destroy(struct bpf_iter__tcp *ctx)
77 {
78 struct sock_common *sk_common = (struct sock_common *)ctx->sk_common;
79 __u64 sock_cookie;
80
81 if (!sk_common)
82 return 0;
83
84 sock_cookie = bpf_get_socket_cookie(sk_common);
85 if (sock_cookie != destroy_cookie)
86 return 0;
87
88 bpf_sock_destroy(sk_common);
89 bpf_seq_write(ctx->meta->seq, &sock_cookie, sizeof(sock_cookie));
90
91 return 0;
92 }
93
94 #define udp_sk(ptr) container_of(ptr, struct udp_sock, inet.sk)
95
96 SEC("iter/udp")
iter_udp_soreuse(struct bpf_iter__udp * ctx)97 int iter_udp_soreuse(struct bpf_iter__udp *ctx)
98 {
99 struct sock *sk = (struct sock *)ctx->udp_sk;
100 struct udp_table *udptable;
101 __u64 sock_cookie;
102 int idx;
103
104 if (!sk)
105 return 0;
106
107 sock_cookie = bpf_get_socket_cookie(sk);
108 sk = bpf_core_cast(sk, struct sock);
109 if (sk->sk_family != sf ||
110 (sk->sk_family == AF_INET6 ?
111 !ipv6_addr_loopback(&sk->sk_v6_rcv_saddr) :
112 !ipv4_addr_loopback(sk->sk_rcv_saddr)))
113 return 0;
114
115 if (sk->sk_num == ports[0])
116 idx = 0;
117 else if (sk->sk_num == ports[1])
118 idx = 1;
119 else if (!ports[0] && !ports[1])
120 idx = 0;
121 else
122 return 0;
123
124 /* bucket selection as in udp_hashslot2() */
125 udptable = sk->sk_net.net->ipv4.udp_table;
126 bucket[idx] = udp_sk(sk)->udp_portaddr_hash & udptable->mask;
127 bpf_seq_write(ctx->meta->seq, &idx, sizeof(idx));
128 bpf_seq_write(ctx->meta->seq, &sock_cookie, sizeof(sock_cookie));
129
130 return 0;
131 }
132
133 char _license[] SEC("license") = "GPL";
134