1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Facebook */
3 #include "bpf_iter.h"
4 #include "bpf_tracing_net.h"
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_endian.h>
7 
8 char _license[] SEC("license") = "GPL";
9 
10 static int hlist_unhashed_lockless(const struct hlist_node *h)
11 {
12         return !(h->pprev);
13 }
14 
15 static int timer_pending(const struct timer_list * timer)
16 {
17 	return !hlist_unhashed_lockless(&timer->entry);
18 }
19 
20 extern unsigned CONFIG_HZ __kconfig;
21 
22 #define USER_HZ		100
23 #define NSEC_PER_SEC	1000000000ULL
24 static clock_t jiffies_to_clock_t(unsigned long x)
25 {
26 	/* The implementation here tailored to a particular
27 	 * setting of USER_HZ.
28 	 */
29 	u64 tick_nsec = (NSEC_PER_SEC + CONFIG_HZ/2) / CONFIG_HZ;
30 	u64 user_hz_nsec = NSEC_PER_SEC / USER_HZ;
31 
32 	if ((tick_nsec % user_hz_nsec) == 0) {
33 		if (CONFIG_HZ < USER_HZ)
34 			return x * (USER_HZ / CONFIG_HZ);
35 		else
36 			return x / (CONFIG_HZ / USER_HZ);
37 	}
38 	return x * tick_nsec/user_hz_nsec;
39 }
40 
41 static clock_t jiffies_delta_to_clock_t(long delta)
42 {
43 	if (delta <= 0)
44 		return 0;
45 
46 	return jiffies_to_clock_t(delta);
47 }
48 
49 static long sock_i_ino(const struct sock *sk)
50 {
51 	const struct socket *sk_socket = sk->sk_socket;
52 	const struct inode *inode;
53 	unsigned long ino;
54 
55 	if (!sk_socket)
56 		return 0;
57 
58 	inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
59 	bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
60 	return ino;
61 }
62 
63 static bool
64 inet_csk_in_pingpong_mode(const struct inet_connection_sock *icsk)
65 {
66 	return icsk->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
67 }
68 
69 static bool tcp_in_initial_slowstart(const struct tcp_sock *tcp)
70 {
71 	return tcp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
72 }
73 
74 static int dump_tcp6_sock(struct seq_file *seq, struct tcp6_sock *tp,
75 			 uid_t uid, __u32 seq_num)
76 {
77 	const struct inet_connection_sock *icsk;
78 	const struct fastopen_queue *fastopenq;
79 	const struct in6_addr *dest, *src;
80 	const struct inet_sock *inet;
81 	unsigned long timer_expires;
82 	const struct sock *sp;
83 	__u16 destp, srcp;
84 	int timer_active;
85 	int rx_queue;
86 	int state;
87 
88 	icsk = &tp->tcp.inet_conn;
89 	inet = &icsk->icsk_inet;
90 	sp = &inet->sk;
91 	fastopenq = &icsk->icsk_accept_queue.fastopenq;
92 
93 	dest = &sp->sk_v6_daddr;
94 	src = &sp->sk_v6_rcv_saddr;
95 	destp = bpf_ntohs(inet->inet_dport);
96 	srcp = bpf_ntohs(inet->inet_sport);
97 
98 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
99 	    icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
100 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
101 		timer_active = 1;
102 		timer_expires = icsk->icsk_timeout;
103 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
104 		timer_active = 4;
105 		timer_expires = icsk->icsk_timeout;
106 	} else if (timer_pending(&sp->sk_timer)) {
107 		timer_active = 2;
108 		timer_expires = sp->sk_timer.expires;
109 	} else {
110 		timer_active = 0;
111 		timer_expires = bpf_jiffies64();
112 	}
113 
114 	state = sp->sk_state;
115 	if (state == TCP_LISTEN) {
116 		rx_queue = sp->sk_ack_backlog;
117 	} else {
118 		rx_queue = tp->tcp.rcv_nxt - tp->tcp.copied_seq;
119 		if (rx_queue < 0)
120 			rx_queue = 0;
121 	}
122 
123 	BPF_SEQ_PRINTF(seq, "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X ",
124 		       seq_num,
125 		       src->s6_addr32[0], src->s6_addr32[1],
126 		       src->s6_addr32[2], src->s6_addr32[3], srcp,
127 		       dest->s6_addr32[0], dest->s6_addr32[1],
128 		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
129 	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d ",
130 		       state,
131 		       tp->tcp.write_seq - tp->tcp.snd_una, rx_queue,
132 		       timer_active,
133 		       jiffies_delta_to_clock_t(timer_expires - bpf_jiffies64()),
134 		       icsk->icsk_retransmits, uid,
135 		       icsk->icsk_probes_out,
136 		       sock_i_ino(sp),
137 		       sp->sk_refcnt.refs.counter);
138 	BPF_SEQ_PRINTF(seq, "%pK %lu %lu %u %u %d\n",
139 		       tp,
140 		       jiffies_to_clock_t(icsk->icsk_rto),
141 		       jiffies_to_clock_t(icsk->icsk_ack.ato),
142 		       (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(icsk),
143 		       tp->tcp.snd_cwnd,
144 		       state == TCP_LISTEN ? fastopenq->max_qlen
145 				: (tcp_in_initial_slowstart(&tp->tcp) ? -1
146 								      : tp->tcp.snd_ssthresh)
147 		      );
148 
149 	return 0;
150 }
151 
152 static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
153 			uid_t uid, __u32 seq_num)
154 {
155 	struct inet_timewait_sock *tw = &ttw->tw_sk;
156 	const struct in6_addr *dest, *src;
157 	__u16 destp, srcp;
158 	long delta;
159 
160 	delta = tw->tw_timer.expires - bpf_jiffies64();
161 	dest = &tw->tw_v6_daddr;
162 	src  = &tw->tw_v6_rcv_saddr;
163 	destp = bpf_ntohs(tw->tw_dport);
164 	srcp  = bpf_ntohs(tw->tw_sport);
165 
166 	BPF_SEQ_PRINTF(seq, "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X ",
167 		       seq_num,
168 		       src->s6_addr32[0], src->s6_addr32[1],
169 		       src->s6_addr32[2], src->s6_addr32[3], srcp,
170 		       dest->s6_addr32[0], dest->s6_addr32[1],
171 		       dest->s6_addr32[2], dest->s6_addr32[3], destp);
172 
173 	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
174 		       tw->tw_substate, 0, 0,
175 		       3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
176 		       tw->tw_refcnt.refs.counter, tw);
177 
178 	return 0;
179 }
180 
181 static int dump_req_sock(struct seq_file *seq, struct tcp_request_sock *treq,
182 			 uid_t uid, __u32 seq_num)
183 {
184 	struct inet_request_sock *irsk = &treq->req;
185 	struct request_sock *req = &irsk->req;
186 	struct in6_addr *src, *dest;
187 	long ttd;
188 
189 	ttd = req->rsk_timer.expires - bpf_jiffies64();
190 	src = &irsk->ir_v6_loc_addr;
191 	dest = &irsk->ir_v6_rmt_addr;
192 
193 	if (ttd < 0)
194 		ttd = 0;
195 
196 	BPF_SEQ_PRINTF(seq, "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X ",
197 		       seq_num,
198 		       src->s6_addr32[0], src->s6_addr32[1],
199 		       src->s6_addr32[2], src->s6_addr32[3],
200 		       irsk->ir_num,
201 		       dest->s6_addr32[0], dest->s6_addr32[1],
202 		       dest->s6_addr32[2], dest->s6_addr32[3],
203 		       bpf_ntohs(irsk->ir_rmt_port));
204 	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
205 		       TCP_SYN_RECV, 0, 0, 1, jiffies_to_clock_t(ttd),
206 		       req->num_timeout, uid, 0, 0, 0, req);
207 
208 	return 0;
209 }
210 
211 SEC("iter/tcp")
212 int dump_tcp6(struct bpf_iter__tcp *ctx)
213 {
214 	struct sock_common *sk_common = ctx->sk_common;
215 	struct seq_file *seq = ctx->meta->seq;
216 	struct tcp_timewait_sock *tw;
217 	struct tcp_request_sock *req;
218 	struct tcp6_sock *tp;
219 	uid_t uid = ctx->uid;
220 	__u32 seq_num;
221 
222 	if (sk_common == (void *)0)
223 		return 0;
224 
225 	seq_num = ctx->meta->seq_num;
226 	if (seq_num == 0)
227 		BPF_SEQ_PRINTF(seq, "  sl  "
228 				    "local_address                         "
229 				    "remote_address                        "
230 				    "st tx_queue rx_queue tr tm->when retrnsmt"
231 				    "   uid  timeout inode\n");
232 
233 	if (sk_common->skc_family != AF_INET6)
234 		return 0;
235 
236 	tp = bpf_skc_to_tcp6_sock(sk_common);
237 	if (tp)
238 		return dump_tcp6_sock(seq, tp, uid, seq_num);
239 
240 	tw = bpf_skc_to_tcp_timewait_sock(sk_common);
241 	if (tw)
242 		return dump_tw_sock(seq, tw, uid, seq_num);
243 
244 	req = bpf_skc_to_tcp_request_sock(sk_common);
245 	if (req)
246 		return dump_req_sock(seq, req, uid, seq_num);
247 
248 	return 0;
249 }
250