aboutgitcodebugslistschat
path: root/util.h
blob: 9446ea7f2aa73a3d09b76d0ce8994345357bf0e1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright (c) 2021 Red Hat GmbH
 * Author: Stefano Brivio <sbrivio@redhat.com>
 */

#ifndef UTIL_H
#define UTIL_H

#include <stdlib.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <signal.h>

#include "log.h"

#define VERSION_BLOB							       \
	VERSION "\n"							       \
	"Copyright Red Hat\n"						       \
	"GNU General Public License, version 2 or later\n"		       \
	"  <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>\n"	       \
	"This is free software: you are free to change and redistribute it.\n" \
	"There is NO WARRANTY, to the extent permitted by law.\n\n"

#ifndef SECCOMP_RET_KILL_PROCESS
#define SECCOMP_RET_KILL_PROCESS	SECCOMP_RET_KILL
#endif
#ifndef ETH_MAX_MTU
#define ETH_MAX_MTU			USHRT_MAX
#endif
#ifndef ETH_MIN_MTU
#define ETH_MIN_MTU			68
#endif

#ifndef MIN
#define MIN(x, y)		(((x) < (y)) ? (x) : (y))
#endif
#ifndef MAX
#define MAX(x, y)		(((x) > (y)) ? (x) : (y))
#endif

#define DIV_ROUND_UP(n, d)	(((n) + (d) - 1) / (d))
#define ROUND_DOWN(x, y)	((x) & ~((y) - 1))
#define ROUND_UP(x, y)		(((x) + (y) - 1) & ~((y) - 1))

#define MAX_FROM_BITS(n)	(((1U << (n)) - 1))

#define BIT(n)			(1UL << (n))
#define BITMAP_BIT(n)		(BIT((n) % (sizeof(long) * 8)))
#define BITMAP_WORD(n)		(n / (sizeof(long) * 8))

#define SWAP(a, b)							\
	do {								\
		__typeof__(a) __x = (a); (a) = (b); (b) = __x;		\
	} while (0)							\

#define STRINGIFY(x)	#x
#define STR(x)		STRINGIFY(x)

#define ASSERT(expr)							\
	do {								\
		if (!(expr)) {						\
			err("ASSERTION FAILED in %s (%s:%d): %s",	\
			    __func__, __FILE__, __LINE__, STRINGIFY(expr)); \
			/* This may actually SIGSYS, due to seccomp,	\
			 * but that will still get the job done		\
			 */						\
			abort();					\
		}							\
	} while (0)

#ifdef P_tmpdir
#define TMPDIR		P_tmpdir
#else
#define TMPDIR		"/tmp"
#endif

#define V4		0
#define V6		1
#define IP_VERSIONS	2

#define ARRAY_SIZE(a)		((int)(sizeof(a) / sizeof((a)[0])))

#define IN_INTERVAL(a, b, x)	((x) >= (a) && (x) <= (b))
#define FD_PROTO(x, proto)						\
	(IN_INTERVAL(c->proto.fd_min, c->proto.fd_max, (x)))

#define PORT_EPHEMERAL_MIN	((1 << 15) + (1 << 14))		/* RFC 6335 */
#define PORT_IS_EPHEMERAL(port) ((port) >= PORT_EPHEMERAL_MIN)

#define MAC_ZERO		((uint8_t [ETH_ALEN]){ 0 })
#define MAC_IS_ZERO(addr)	(!memcmp((addr), MAC_ZERO, ETH_ALEN))

#ifndef __bswap_constant_16
#define __bswap_constant_16(x)						\
	((uint16_t) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
#endif

#ifndef __bswap_constant_32
#define __bswap_constant_32(x)						\
	((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) |	\
	 (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
#endif

#if __BYTE_ORDER == __BIG_ENDIAN
#define	htons_constant(x)	(x)
#define	htonl_constant(x)	(x)
#else
#define	htons_constant(x)	(__bswap_constant_16(x))
#define	htonl_constant(x)	(__bswap_constant_32(x))
#endif

#define IN4_IS_ADDR_UNSPECIFIED(a) \
	((a)->s_addr == htonl(INADDR_ANY))
#define IN4_IS_ADDR_BROADCAST(a) \
	((a)->s_addr == htonl(INADDR_BROADCAST))
#define IN4_IS_ADDR_LOOPBACK(a) \
	(ntohl((a)->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
#define IN4_IS_ADDR_MULTICAST(a) \
	(IN_MULTICAST(ntohl((a)->s_addr)))
#define IN4_ARE_ADDR_EQUAL(a, b) \
	(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
#define IN4ADDR_LOOPBACK_INIT \
	{ .s_addr	= htonl_constant(INADDR_LOOPBACK) }

#define NS_FN_STACK_SIZE	(RLIMIT_STACK_VAL * 1024 / 8)
int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
	     void *arg);
#define NS_CALL(fn, arg)						\
	do {								\
		char ns_fn_stack[NS_FN_STACK_SIZE];			\
									\
		do_clone((fn), ns_fn_stack, sizeof(ns_fn_stack),	\
			 CLONE_VM | CLONE_VFORK | CLONE_FILES | SIGCHLD,\
			 (void *)(arg));				\
	} while (0)

#define L2_BUF_IP4_INIT(proto)						\
	{								\
		.version	= 4,					\
		.ihl		= 5,					\
		.tos		= 0,					\
		.tot_len	= 0,					\
		.id		= 0,					\
		.frag_off	= 0,					\
		.ttl		= 0xff,					\
		.protocol	= (proto),				\
		.saddr		= 0,					\
		.daddr		= 0,					\
	}
#define L2_BUF_IP4_PSUM(proto)	((uint32_t)htons_constant(0x4500) +	\
				 (uint32_t)htons_constant(0xff00 | (proto)))

#define L2_BUF_IP6_INIT(proto)						\
	{								\
		.priority	= 0,					\
		.version	= 6,					\
		.flow_lbl	= { 0 },				\
		.payload_len	= 0,					\
		.nexthdr	= (proto),				\
		.hop_limit	= 255,					\
		.saddr		= IN6ADDR_ANY_INIT,			\
		.daddr		= IN6ADDR_ANY_INIT,			\
	}

#define RCVBUF_BIG		(2UL * 1024 * 1024)
#define SNDBUF_BIG		(4UL * 1024 * 1024)
#define SNDBUF_SMALL		(128UL * 1024)

#include <net/if.h>
#include <limits.h>
#include <stdint.h>
#include <netinet/ip6.h>

#include "packet.h"

struct ctx;

struct ipv6hdr {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
#if __BYTE_ORDER == __BIG_ENDIAN
	uint8_t			version:4,
				priority:4;
#else
	uint8_t			priority:4,
				version:4;
#endif
#pragma GCC diagnostic pop
	uint8_t			flow_lbl[3];

	uint16_t		payload_len;
	uint8_t			nexthdr;
	uint8_t			hop_limit;

	struct in6_addr		saddr;
	struct in6_addr		daddr;
};

struct ipv6_opt_hdr {
	uint8_t			nexthdr;
	uint8_t			hdrlen;
	/*
	 * TLV encoded option data follows.
	 */
} __attribute__((packed));	/* required for some archs */

/* cppcheck-suppress funcArgNamesDifferent */
__attribute__ ((weak)) int ffsl(long int i) { return __builtin_ffsl(i); }
char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
		 size_t *dlen);
int sock_l4(const struct ctx *c, int af, uint8_t proto,
	    const void *bind_addr, const char *ifname, uint16_t port,
	    uint32_t data);
void sock_probe_mem(struct ctx *c);
int timespec_diff_ms(const struct timespec *a, const struct timespec *b);
void bitmap_set(uint8_t *map, int bit);
void bitmap_clear(uint8_t *map, int bit);
int bitmap_isset(const uint8_t *map, int bit);
void bitmap_or(uint8_t *dst, size_t size, const uint8_t *a, const uint8_t *b);
char *line_read(char *buf, size_t len, int fd);
void ns_enter(const struct ctx *c);
bool ns_is_init(void);
int open_in_ns(const struct ctx *c, const char *path, int flags);
void write_pidfile(int fd, pid_t pid);
int __daemon(int pidfile_fd, int devnull_fd);
int fls(unsigned long x);
int write_file(const char *path, const char *buf);

/**
 * mod_sub() - Modular arithmetic subtraction
 * @a:		Minued, unsigned value < @m
 * @b:		Subtrahend, unsigned value < @m
 * @m:		Modulus, must be less than (UINT_MAX / 2)
 *
 * Returns (@a - @b) mod @m, correctly handling unsigned underflows.
 */
static inline unsigned mod_sub(unsigned a, unsigned b, unsigned m)
{
	if (a < b)
		a += m;
	return a - b;
}

/**
 * mod_between() - Determine if a value is in a cyclic range
 * @x, @i, @j:	Unsigned values < @m
 * @m:		Modulus
 *
 * Returns true iff @x is in the cyclic range of values from @i..@j (mod @m),
 * inclusive of @i, exclusive of @j.
 */
static inline bool mod_between(unsigned x, unsigned i, unsigned j, unsigned m)
{
	return mod_sub(x, i, m) < mod_sub(j, i, m);
}

/*
 * Workarounds for https://github.com/llvm/llvm-project/issues/58992
 *
 * For a number (maybe all) system calls that _write_ a socket address,
 * clang-tidy doesn't register that the memory of the socket address will be
 * initialised after the call.  This can't easily be worked around with
 * clang-tidy suppressions, because the warning doesn't show on the syscall
 * itself but later when we access the supposedly uninitialised field.
 */
static inline void sa_init(struct sockaddr *sa, const socklen_t *sl)
{
#ifdef CLANG_TIDY_58992
	if (sa)
		memset(sa, 0, *sl);
#else
	(void)sa;
	(void)sl;
#endif /* CLANG_TIDY_58992 */
}

static inline ssize_t wrap_recvfrom(int sockfd, void *buf, size_t len,
				    int flags,
				    struct sockaddr *src_addr,
				    socklen_t *addrlen)
{
	sa_init(src_addr, addrlen);
	return recvfrom(sockfd, buf, len, flags, src_addr, addrlen);
}
#define recvfrom(s, buf, len, flags, src, addrlen)		\
	wrap_recvfrom((s), (buf), (len), (flags), (src), (addrlen))

static inline int wrap_accept4(int sockfd, struct sockaddr *addr,
			       socklen_t *addrlen, int flags)
{
	sa_init(addr, addrlen);
	return accept4(sockfd, addr, addrlen, flags);
}
#define accept4(s, addr, addrlen, flags) \
	wrap_accept4((s), (addr), (addrlen), (flags))

#endif /* UTIL_H */