sk_so_peek_off.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3#include <stdio.h>
  4#include <stdlib.h>
  5#include <string.h>
  6#include <unistd.h>
  7#include <errno.h>
  8#include <sys/types.h>
  9#include <netinet/in.h>
 10#include <arpa/inet.h>
 11#include "kselftest.h"
 12
 13static char *afstr(int af, int proto)
 14{
 15	if (proto == IPPROTO_TCP)
 16		return af == AF_INET ? "TCP/IPv4" : "TCP/IPv6";
 17	else
 18		return af == AF_INET ? "UDP/IPv4" : "UDP/IPv6";
 19}
 20
 21int sk_peek_offset_probe(sa_family_t af, int proto)
 22{
 23	int type = (proto == IPPROTO_TCP ? SOCK_STREAM : SOCK_DGRAM);
 24	int optv = 0;
 25	int ret = 0;
 26	int s;
 27
 28	s = socket(af, type, proto);
 29	if (s < 0) {
 30		ksft_perror("Temporary TCP socket creation failed");
 31	} else {
 32		if (!setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &optv, sizeof(int)))
 33			ret = 1;
 34		else
 35			printf("%s does not support SO_PEEK_OFF\n", afstr(af, proto));
 36		close(s);
 37	}
 38	return ret;
 39}
 40
 41static void sk_peek_offset_set(int s, int offset)
 42{
 43	if (setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, sizeof(offset)))
 44		ksft_perror("Failed to set SO_PEEK_OFF value\n");
 45}
 46
 47static int sk_peek_offset_get(int s)
 48{
 49	int offset;
 50	socklen_t len = sizeof(offset);
 51
 52	if (getsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &offset, &len))
 53		ksft_perror("Failed to get SO_PEEK_OFF value\n");
 54	return offset;
 55}
 56
 57static int sk_peek_offset_test(sa_family_t af, int proto)
 58{
 59	int type = (proto == IPPROTO_TCP ? SOCK_STREAM : SOCK_DGRAM);
 60	union {
 61		struct sockaddr sa;
 62		struct sockaddr_in a4;
 63		struct sockaddr_in6 a6;
 64	} a;
 65	int res = 0;
 66	int s[2] = {0, 0};
 67	int recv_sock = 0;
 68	int offset = 0;
 69	ssize_t len;
 70	char buf[2];
 71
 72	memset(&a, 0, sizeof(a));
 73	a.sa.sa_family = af;
 74
 75	s[0] = recv_sock = socket(af, type, proto);
 76	s[1] = socket(af, type, proto);
 77
 78	if (s[0] < 0 || s[1] < 0) {
 79		ksft_perror("Temporary socket creation failed\n");
 80		goto out;
 81	}
 82	if (bind(s[0], &a.sa, sizeof(a)) < 0) {
 83		ksft_perror("Temporary socket bind() failed\n");
 84		goto out;
 85	}
 86	if (getsockname(s[0], &a.sa, &((socklen_t) { sizeof(a) })) < 0) {
 87		ksft_perror("Temporary socket getsockname() failed\n");
 88		goto out;
 89	}
 90	if (proto == IPPROTO_TCP && listen(s[0], 0) < 0) {
 91		ksft_perror("Temporary socket listen() failed\n");
 92		goto out;
 93	}
 94	if (connect(s[1], &a.sa, sizeof(a)) < 0) {
 95		ksft_perror("Temporary socket connect() failed\n");
 96		goto out;
 97	}
 98	if (proto == IPPROTO_TCP) {
 99		recv_sock = accept(s[0], NULL, NULL);
100		if (recv_sock <= 0) {
101			ksft_perror("Temporary socket accept() failed\n");
102			goto out;
103		}
104	}
105
106	/* Some basic tests of getting/setting offset */
107	offset = sk_peek_offset_get(recv_sock);
108	if (offset != -1) {
109		ksft_perror("Initial value of socket offset not -1\n");
110		goto out;
111	}
112	sk_peek_offset_set(recv_sock, 0);
113	offset = sk_peek_offset_get(recv_sock);
114	if (offset != 0) {
115		ksft_perror("Failed to set socket offset to 0\n");
116		goto out;
117	}
118
119	/* Transfer a message */
120	if (send(s[1], (char *)("ab"), 2, 0) != 2) {
121		ksft_perror("Temporary probe socket send() failed\n");
122		goto out;
123	}
124	/* Read first byte */
125	len = recv(recv_sock, buf, 1, MSG_PEEK);
126	if (len != 1 || buf[0] != 'a') {
127		ksft_perror("Failed to read first byte of message\n");
128		goto out;
129	}
130	offset = sk_peek_offset_get(recv_sock);
131	if (offset != 1) {
132		ksft_perror("Offset not forwarded correctly at first byte\n");
133		goto out;
134	}
135	/* Try to read beyond last byte */
136	len = recv(recv_sock, buf, 2, MSG_PEEK);
137	if (len != 1 || buf[0] != 'b') {
138		ksft_perror("Failed to read last byte of message\n");
139		goto out;
140	}
141	offset = sk_peek_offset_get(recv_sock);
142	if (offset != 2) {
143		ksft_perror("Offset not forwarded correctly at last byte\n");
144		goto out;
145	}
146	/* Flush message */
147	len = recv(recv_sock, buf, 2, MSG_TRUNC);
148	if (len != 2) {
149		ksft_perror("Failed to flush message\n");
150		goto out;
151	}
152	offset = sk_peek_offset_get(recv_sock);
153	if (offset != 0) {
154		ksft_perror("Offset not reverted correctly after flush\n");
155		goto out;
156	}
157
158	printf("%s with MSG_PEEK_OFF works correctly\n", afstr(af, proto));
159	res = 1;
160out:
161	if (proto == IPPROTO_TCP && recv_sock >= 0)
162		close(recv_sock);
163	if (s[1] >= 0)
164		close(s[1]);
165	if (s[0] >= 0)
166		close(s[0]);
167	return res;
168}
169
170static int do_test(int proto)
171{
172	int res4, res6;
173
174	res4 = sk_peek_offset_probe(AF_INET, proto);
175	res6 = sk_peek_offset_probe(AF_INET6, proto);
176
177	if (!res4 && !res6)
178		return KSFT_SKIP;
179
180	if (res4)
181		res4 = sk_peek_offset_test(AF_INET, proto);
182
183	if (res6)
184		res6 = sk_peek_offset_test(AF_INET6, proto);
185
186	if (!res4 || !res6)
187		return KSFT_FAIL;
188
189	return KSFT_PASS;
190}
191
192int main(void)
193{
194	int restcp, resudp;
195
196	restcp = do_test(IPPROTO_TCP);
197	resudp = do_test(IPPROTO_UDP);
198	if (restcp == KSFT_FAIL || resudp == KSFT_FAIL)
199		return KSFT_FAIL;
200
201	return KSFT_PASS;
202}