1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright 2018 Google Inc.
4*4882a593Smuzhiyun * Author: Soheil Hassas Yeganeh (soheil@google.com)
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Simple example on how to use TCP_INQ and TCP_CM_INQ.
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun #define _GNU_SOURCE
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <error.h>
11*4882a593Smuzhiyun #include <netinet/in.h>
12*4882a593Smuzhiyun #include <netinet/tcp.h>
13*4882a593Smuzhiyun #include <pthread.h>
14*4882a593Smuzhiyun #include <stdio.h>
15*4882a593Smuzhiyun #include <errno.h>
16*4882a593Smuzhiyun #include <stdlib.h>
17*4882a593Smuzhiyun #include <string.h>
18*4882a593Smuzhiyun #include <sys/socket.h>
19*4882a593Smuzhiyun #include <unistd.h>
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun #ifndef TCP_INQ
22*4882a593Smuzhiyun #define TCP_INQ 36
23*4882a593Smuzhiyun #endif
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun #ifndef TCP_CM_INQ
26*4882a593Smuzhiyun #define TCP_CM_INQ TCP_INQ
27*4882a593Smuzhiyun #endif
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun #define BUF_SIZE 8192
30*4882a593Smuzhiyun #define CMSG_SIZE 32
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun static int family = AF_INET6;
33*4882a593Smuzhiyun static socklen_t addr_len = sizeof(struct sockaddr_in6);
34*4882a593Smuzhiyun static int port = 4974;
35*4882a593Smuzhiyun
setup_loopback_addr(int family,struct sockaddr_storage * sockaddr)36*4882a593Smuzhiyun static void setup_loopback_addr(int family, struct sockaddr_storage *sockaddr)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun struct sockaddr_in6 *addr6 = (void *) sockaddr;
39*4882a593Smuzhiyun struct sockaddr_in *addr4 = (void *) sockaddr;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun switch (family) {
42*4882a593Smuzhiyun case PF_INET:
43*4882a593Smuzhiyun memset(addr4, 0, sizeof(*addr4));
44*4882a593Smuzhiyun addr4->sin_family = AF_INET;
45*4882a593Smuzhiyun addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
46*4882a593Smuzhiyun addr4->sin_port = htons(port);
47*4882a593Smuzhiyun break;
48*4882a593Smuzhiyun case PF_INET6:
49*4882a593Smuzhiyun memset(addr6, 0, sizeof(*addr6));
50*4882a593Smuzhiyun addr6->sin6_family = AF_INET6;
51*4882a593Smuzhiyun addr6->sin6_addr = in6addr_loopback;
52*4882a593Smuzhiyun addr6->sin6_port = htons(port);
53*4882a593Smuzhiyun break;
54*4882a593Smuzhiyun default:
55*4882a593Smuzhiyun error(1, 0, "illegal family");
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun
start_server(void * arg)59*4882a593Smuzhiyun void *start_server(void *arg)
60*4882a593Smuzhiyun {
61*4882a593Smuzhiyun int server_fd = (int)(unsigned long)arg;
62*4882a593Smuzhiyun struct sockaddr_in addr;
63*4882a593Smuzhiyun socklen_t addrlen = sizeof(addr);
64*4882a593Smuzhiyun char *buf;
65*4882a593Smuzhiyun int fd;
66*4882a593Smuzhiyun int r;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun buf = malloc(BUF_SIZE);
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun for (;;) {
71*4882a593Smuzhiyun fd = accept(server_fd, (struct sockaddr *)&addr, &addrlen);
72*4882a593Smuzhiyun if (fd == -1) {
73*4882a593Smuzhiyun perror("accept");
74*4882a593Smuzhiyun break;
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun do {
77*4882a593Smuzhiyun r = send(fd, buf, BUF_SIZE, 0);
78*4882a593Smuzhiyun } while (r < 0 && errno == EINTR);
79*4882a593Smuzhiyun if (r < 0)
80*4882a593Smuzhiyun perror("send");
81*4882a593Smuzhiyun if (r != BUF_SIZE)
82*4882a593Smuzhiyun fprintf(stderr, "can only send %d bytes\n", r);
83*4882a593Smuzhiyun /* TCP_INQ can overestimate in-queue by one byte if we send
84*4882a593Smuzhiyun * the FIN packet. Sleep for 1 second, so that the client
85*4882a593Smuzhiyun * likely invoked recvmsg().
86*4882a593Smuzhiyun */
87*4882a593Smuzhiyun sleep(1);
88*4882a593Smuzhiyun close(fd);
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun free(buf);
92*4882a593Smuzhiyun close(server_fd);
93*4882a593Smuzhiyun pthread_exit(0);
94*4882a593Smuzhiyun }
95*4882a593Smuzhiyun
main(int argc,char * argv[])96*4882a593Smuzhiyun int main(int argc, char *argv[])
97*4882a593Smuzhiyun {
98*4882a593Smuzhiyun struct sockaddr_storage listen_addr, addr;
99*4882a593Smuzhiyun int c, one = 1, inq = -1;
100*4882a593Smuzhiyun pthread_t server_thread;
101*4882a593Smuzhiyun char cmsgbuf[CMSG_SIZE];
102*4882a593Smuzhiyun struct iovec iov[1];
103*4882a593Smuzhiyun struct cmsghdr *cm;
104*4882a593Smuzhiyun struct msghdr msg;
105*4882a593Smuzhiyun int server_fd, fd;
106*4882a593Smuzhiyun char *buf;
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun while ((c = getopt(argc, argv, "46p:")) != -1) {
109*4882a593Smuzhiyun switch (c) {
110*4882a593Smuzhiyun case '4':
111*4882a593Smuzhiyun family = PF_INET;
112*4882a593Smuzhiyun addr_len = sizeof(struct sockaddr_in);
113*4882a593Smuzhiyun break;
114*4882a593Smuzhiyun case '6':
115*4882a593Smuzhiyun family = PF_INET6;
116*4882a593Smuzhiyun addr_len = sizeof(struct sockaddr_in6);
117*4882a593Smuzhiyun break;
118*4882a593Smuzhiyun case 'p':
119*4882a593Smuzhiyun port = atoi(optarg);
120*4882a593Smuzhiyun break;
121*4882a593Smuzhiyun }
122*4882a593Smuzhiyun }
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun server_fd = socket(family, SOCK_STREAM, 0);
125*4882a593Smuzhiyun if (server_fd < 0)
126*4882a593Smuzhiyun error(1, errno, "server socket");
127*4882a593Smuzhiyun setup_loopback_addr(family, &listen_addr);
128*4882a593Smuzhiyun if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR,
129*4882a593Smuzhiyun &one, sizeof(one)) != 0)
130*4882a593Smuzhiyun error(1, errno, "setsockopt(SO_REUSEADDR)");
131*4882a593Smuzhiyun if (bind(server_fd, (const struct sockaddr *)&listen_addr,
132*4882a593Smuzhiyun addr_len) == -1)
133*4882a593Smuzhiyun error(1, errno, "bind");
134*4882a593Smuzhiyun if (listen(server_fd, 128) == -1)
135*4882a593Smuzhiyun error(1, errno, "listen");
136*4882a593Smuzhiyun if (pthread_create(&server_thread, NULL, start_server,
137*4882a593Smuzhiyun (void *)(unsigned long)server_fd) != 0)
138*4882a593Smuzhiyun error(1, errno, "pthread_create");
139*4882a593Smuzhiyun
140*4882a593Smuzhiyun fd = socket(family, SOCK_STREAM, 0);
141*4882a593Smuzhiyun if (fd < 0)
142*4882a593Smuzhiyun error(1, errno, "client socket");
143*4882a593Smuzhiyun setup_loopback_addr(family, &addr);
144*4882a593Smuzhiyun if (connect(fd, (const struct sockaddr *)&addr, addr_len) == -1)
145*4882a593Smuzhiyun error(1, errno, "connect");
146*4882a593Smuzhiyun if (setsockopt(fd, SOL_TCP, TCP_INQ, &one, sizeof(one)) != 0)
147*4882a593Smuzhiyun error(1, errno, "setsockopt(TCP_INQ)");
148*4882a593Smuzhiyun
149*4882a593Smuzhiyun msg.msg_name = NULL;
150*4882a593Smuzhiyun msg.msg_namelen = 0;
151*4882a593Smuzhiyun msg.msg_iov = iov;
152*4882a593Smuzhiyun msg.msg_iovlen = 1;
153*4882a593Smuzhiyun msg.msg_control = cmsgbuf;
154*4882a593Smuzhiyun msg.msg_controllen = sizeof(cmsgbuf);
155*4882a593Smuzhiyun msg.msg_flags = 0;
156*4882a593Smuzhiyun
157*4882a593Smuzhiyun buf = malloc(BUF_SIZE);
158*4882a593Smuzhiyun iov[0].iov_base = buf;
159*4882a593Smuzhiyun iov[0].iov_len = BUF_SIZE / 2;
160*4882a593Smuzhiyun
161*4882a593Smuzhiyun if (recvmsg(fd, &msg, 0) != iov[0].iov_len)
162*4882a593Smuzhiyun error(1, errno, "recvmsg");
163*4882a593Smuzhiyun if (msg.msg_flags & MSG_CTRUNC)
164*4882a593Smuzhiyun error(1, 0, "control message is truncated");
165*4882a593Smuzhiyun
166*4882a593Smuzhiyun for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm))
167*4882a593Smuzhiyun if (cm->cmsg_level == SOL_TCP && cm->cmsg_type == TCP_CM_INQ)
168*4882a593Smuzhiyun inq = *((int *) CMSG_DATA(cm));
169*4882a593Smuzhiyun
170*4882a593Smuzhiyun if (inq != BUF_SIZE - iov[0].iov_len) {
171*4882a593Smuzhiyun fprintf(stderr, "unexpected inq: %d\n", inq);
172*4882a593Smuzhiyun exit(1);
173*4882a593Smuzhiyun }
174*4882a593Smuzhiyun
175*4882a593Smuzhiyun printf("PASSED\n");
176*4882a593Smuzhiyun free(buf);
177*4882a593Smuzhiyun close(fd);
178*4882a593Smuzhiyun return 0;
179*4882a593Smuzhiyun }
180