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passt/util.h
David Gibson 2fa91ee391 udp: Handle errors on UDP sockets
Currently we ignore all events other than EPOLLIN on UDP sockets.  This
means that if we ever receive an EPOLLERR event, we'll enter an infinite
loop on epoll, because we'll never do anything to clear the error.

Luckily that doesn't seem to have happened in practice, but it's certainly
fragile.  Furthermore changes in how we handle UDP sockets with the flow
table mean we will start receiving error events.

Add handling of EPOLLERR events.  For now we just read the error from the
error queue (thereby clearing the error state) and print a debug message.
We can add more substantial handling of specific events in future if we
want to.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-07-17 07:05:21 +02:00

271 lines
7.7 KiB
C

/* 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 <stddef.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 IP_MAX_MTU
#define IP_MAX_MTU USHRT_MAX
#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 DIV_ROUND_CLOSEST(n, d) (((n) + (d) / 2) / (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_LAA ((uint8_t [ETH_ALEN]){ BIT(1), 0, 0, 0, 0, 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 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] \
__attribute__ ((aligned(__alignof__(max_align_t)))); \
\
do_clone((fn), ns_fn_stack, sizeof(ns_fn_stack), \
CLONE_VM | CLONE_VFORK | CLONE_FILES | SIGCHLD,\
(void *)(arg)); \
} while (0)
#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 "epoll_type.h"
#include "packet.h"
struct ctx;
/* cppcheck-suppress funcArgNamesDifferent */
__attribute__ ((weak)) int ffsl(long int i) { return __builtin_ffsl(i); }
int sock_l4(const struct ctx *c, sa_family_t af, enum epoll_type type,
const void *bind_addr, const char *ifname, uint16_t port,
uint32_t data);
void sock_probe_mem(struct ctx *c);
long timespec_diff_ms(const struct timespec *a, const struct timespec *b);
void bitmap_set(uint8_t *map, unsigned bit);
void bitmap_clear(uint8_t *map, unsigned bit);
bool bitmap_isset(const uint8_t *map, unsigned 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);
int pidfile_open(const char *path);
void pidfile_write(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);
int write_remainder(int fd, const struct iovec *iov, int iovcnt, size_t skip);
/**
* af_name() - Return name of an address family
* @af: Address/protocol family (AF_INET or AF_INET6)
*
* Returns: Name of the protocol family as a string
*/
static inline const char *af_name(sa_family_t af)
{
switch (af) {
case AF_INET:
return "IPv4";
case AF_INET6:
return "IPv6";
default:
return "<unknown address family>";
}
}
#define UINT16_STRLEN (sizeof("65535"))
/* inet address (- '\0') + port (u16) (- '\0') + ':' + '\0' */
#define SOCKADDR_INET_STRLEN \
(INET_ADDRSTRLEN-1 + UINT16_STRLEN-1 + sizeof(":"))
/* inet6 address (- '\0') + port (u16) (- '\0') + '[' + ']' + ':' + '\0' */
#define SOCKADDR_INET6_STRLEN \
(INET6_ADDRSTRLEN-1 + UINT16_STRLEN-1 + sizeof("[]:"))
#define SOCKADDR_STRLEN MAX(SOCKADDR_INET_STRLEN, SOCKADDR_INET6_STRLEN)
struct sock_extended_err;
const char *sockaddr_ntop(const void *sa, char *dst, socklen_t size);
const char *str_ee_origin(const struct sock_extended_err *ee);
/**
* 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 */