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We partially prepopulate IP and TCP header structures including, amongst
other things the destination address, which for IPv4 is always the known
address of the guest/namespace. We partially precompute both the IPv4
header checksum and the TCP checksum based on this.
In future we're going to want more flexibility with controlling the
destination for IPv4 (as we already do for IPv6), so this precomputed value
gets in the way. Therefore remove the IPv4 destination from the
precomputed checksum and fold it into the checksum update when we actually
send a packet.
Doing this means we no longer need to recompute those partial sums when
the destination address changes ({tcp,udp}_update_l2_buf()) and instead
the computation can be moved to compile time. This means while we perform
slightly more computations on each packet, we slightly reduce the amount of
memory we need to access.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
229 lines
6.1 KiB
C
229 lines
6.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#ifndef UTIL_H
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#define UTIL_H
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include "log.h"
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#define VERSION_BLOB \
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VERSION "\n" \
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"Copyright Red Hat\n" \
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"GNU Affero GPL version 3 or later " \
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"<https://www.gnu.org/licenses/agpl-3.0.html>\n" \
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"This is free software: you are free to change and redistribute it.\n" \
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"There is NO WARRANTY, to the extent permitted by law.\n\n"
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#ifndef SECCOMP_RET_KILL_PROCESS
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#define SECCOMP_RET_KILL_PROCESS SECCOMP_RET_KILL
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#endif
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#ifndef ETH_MAX_MTU
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#define ETH_MAX_MTU USHRT_MAX
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#endif
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#ifndef ETH_MIN_MTU
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#define ETH_MIN_MTU 68
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#endif
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#ifndef MIN
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#define MIN(x, y) (((x) < (y)) ? (x) : (y))
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#endif
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#ifndef MAX
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#define MAX(x, y) (((x) > (y)) ? (x) : (y))
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#endif
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#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
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#define ROUND_DOWN(x, y) ((x) & ~((y) - 1))
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#define ROUND_UP(x, y) (((x) + (y) - 1) & ~((y) - 1))
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#define MAX_FROM_BITS(n) ((int)((1U << (n)) - 1))
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#define BIT(n) (1UL << (n))
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#define BITMAP_BIT(n) (BIT((n) % (sizeof(long) * 8)))
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#define BITMAP_WORD(n) (n / (sizeof(long) * 8))
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#define SWAP(a, b) \
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do { \
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__typeof__(a) __x = (a); (a) = (b); (b) = __x; \
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} while (0) \
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#define STRINGIFY(x) #x
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#define STR(x) STRINGIFY(x)
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#define ASSERT(expr) \
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do { \
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if (!(expr)) { \
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err("ASSERTION FAILED in %s (%s:%d): %s", \
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__func__, __FILE__, __LINE__, STRINGIFY(expr)); \
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/* This may actually SIGSYS, due to seccomp, \
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* but that will still get the job done \
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*/ \
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abort(); \
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} \
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} while (0)
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#ifdef P_tmpdir
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#define TMPDIR P_tmpdir
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#else
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#define TMPDIR "/tmp"
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#endif
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#define V4 0
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#define V6 1
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#define IP_VERSIONS 2
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#define ARRAY_SIZE(a) ((int)(sizeof(a) / sizeof((a)[0])))
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#define IN_INTERVAL(a, b, x) ((x) >= (a) && (x) <= (b))
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#define FD_PROTO(x, proto) \
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(IN_INTERVAL(c->proto.fd_min, c->proto.fd_max, (x)))
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#define PORT_EPHEMERAL_MIN ((1 << 15) + (1 << 14)) /* RFC 6335 */
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#define PORT_IS_EPHEMERAL(port) ((port) >= PORT_EPHEMERAL_MIN)
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#define MAC_ZERO ((uint8_t [ETH_ALEN]){ 0 })
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#define MAC_IS_ZERO(addr) (!memcmp((addr), MAC_ZERO, ETH_ALEN))
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#ifndef __bswap_constant_16
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#define __bswap_constant_16(x) \
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((uint16_t) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
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#endif
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#ifndef __bswap_constant_32
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#define __bswap_constant_32(x) \
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((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
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(((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
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#endif
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#if __BYTE_ORDER == __BIG_ENDIAN
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#define htons_constant(x) (x)
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#define htonl_constant(x) (x)
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#else
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#define htons_constant(x) (__bswap_constant_16(x))
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#define htonl_constant(x) (__bswap_constant_32(x))
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#endif
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#define IN4_IS_ADDR_UNSPECIFIED(a) \
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((a)->s_addr == htonl(INADDR_ANY))
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#define IN4_IS_ADDR_BROADCAST(a) \
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((a)->s_addr == htonl(INADDR_BROADCAST))
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#define IN4_IS_ADDR_LOOPBACK(a) \
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(ntohl((a)->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
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#define IN4_IS_ADDR_MULTICAST(a) \
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(IN_MULTICAST(ntohl((a)->s_addr)))
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#define IN4_ARE_ADDR_EQUAL(a, b) \
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(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
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#define IN4ADDR_LOOPBACK_INIT \
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{ .s_addr = htonl_constant(INADDR_LOOPBACK) }
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#define NS_FN_STACK_SIZE (RLIMIT_STACK_VAL * 1024 / 8)
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int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
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void *arg);
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#define NS_CALL(fn, arg) \
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do { \
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char ns_fn_stack[NS_FN_STACK_SIZE]; \
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\
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do_clone((fn), ns_fn_stack, sizeof(ns_fn_stack), \
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CLONE_VM | CLONE_VFORK | CLONE_FILES | SIGCHLD,\
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(void *)(arg)); \
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} while (0)
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#define L2_BUF_IP4_INIT(proto) \
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{ \
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.version = 4, \
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.ihl = 5, \
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.tos = 0, \
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.tot_len = 0, \
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.id = 0, \
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.frag_off = 0, \
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.ttl = 0xff, \
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.protocol = (proto), \
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.saddr = 0, \
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.daddr = 0, \
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}
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#define L2_BUF_IP4_PSUM(proto) ((uint32_t)htons_constant(0x4500) + \
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(uint32_t)htons_constant(0xff00 | (proto)))
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#define L2_BUF_IP6_INIT(proto) \
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{ \
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.priority = 0, \
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.version = 6, \
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.flow_lbl = { 0 }, \
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.payload_len = 0, \
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.nexthdr = (proto), \
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.hop_limit = 255, \
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.saddr = IN6ADDR_ANY_INIT, \
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.daddr = IN6ADDR_ANY_INIT, \
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}
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#define RCVBUF_BIG (2UL * 1024 * 1024)
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#define SNDBUF_BIG (4UL * 1024 * 1024)
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#define SNDBUF_SMALL (128UL * 1024)
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#include <net/if.h>
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#include <limits.h>
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#include <stdint.h>
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#include <netinet/ip6.h>
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#include "packet.h"
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struct ctx;
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struct ipv6hdr {
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wpedantic"
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#if __BYTE_ORDER == __BIG_ENDIAN
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uint8_t version:4,
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priority:4;
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#else
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uint8_t priority:4,
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version:4;
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#endif
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#pragma GCC diagnostic pop
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uint8_t flow_lbl[3];
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uint16_t payload_len;
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uint8_t nexthdr;
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uint8_t hop_limit;
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struct in6_addr saddr;
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struct in6_addr daddr;
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};
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struct ipv6_opt_hdr {
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uint8_t nexthdr;
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uint8_t hdrlen;
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/*
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* TLV encoded option data follows.
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*/
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} __attribute__((packed)); /* required for some archs */
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/* cppcheck-suppress funcArgNamesDifferent */
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__attribute__ ((weak)) int ffsl(long int i) { return __builtin_ffsl(i); }
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char *ipv6_l4hdr(const struct pool *p, int index, size_t offset, uint8_t *proto,
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size_t *dlen);
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int sock_l4(const struct ctx *c, int af, uint8_t proto,
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const void *bind_addr, const char *ifname, uint16_t port,
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uint32_t data);
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void sock_probe_mem(struct ctx *c);
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int timespec_diff_ms(const struct timespec *a, const struct timespec *b);
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void bitmap_set(uint8_t *map, int bit);
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void bitmap_clear(uint8_t *map, int bit);
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int bitmap_isset(const uint8_t *map, int bit);
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char *line_read(char *buf, size_t len, int fd);
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void procfs_scan_listen(struct ctx *c, uint8_t proto, int ip_version, int ns,
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uint8_t *map, uint8_t *exclude);
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void ns_enter(const struct ctx *c);
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bool ns_is_init(void);
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void write_pidfile(int fd, pid_t pid);
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int __daemon(int pidfile_fd, int devnull_fd);
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int fls(unsigned long x);
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int write_file(const char *path, const char *buf);
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#endif /* UTIL_H */
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