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// SPDX-License-Identifier: GPL-2.0-or-later
/* PASST - Plug A Simple Socket Transport
* for qemu/UNIX domain socket mode
*
* PASTA - Pack A Subtle Tap Abstraction
* for network namespace/tap device mode
*
* ip.c - IP related functions
*
* Copyright (c) 2020-2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#include <stddef.h>
#include "util.h"
#include "ip.h"
#define IPV6_NH_OPT(nh) \
((nh) == 0 || (nh) == 43 || (nh) == 44 || (nh) == 50 || \
(nh) == 51 || (nh) == 60 || (nh) == 135 || (nh) == 139 || \
(nh) == 140 || (nh) == 253 || (nh) == 254)
/**
* ipv6_l4hdr() - Find pointer to L4 header in IPv6 packet and extract protocol
* @p: Packet pool, packet number @idx has IPv6 header at @offset
* @idx: Index of packet in pool
* @offset: Pre-calculated IPv6 header offset
* @proto: Filled with L4 protocol number
* @dlen: Data length (payload excluding header extensions), set on return
*
* Return: pointer to L4 header, NULL if not found
*/
char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
size_t *dlen)
{
const struct ipv6_opt_hdr *o;
const struct ipv6hdr *ip6h;
char *base;
int hdrlen;
uint8_t nh;
base = packet_get(p, idx, 0, 0, NULL);
ip6h = packet_get(p, idx, offset, sizeof(*ip6h), dlen);
if (!ip6h)
return NULL;
offset += sizeof(*ip6h);
nh = ip6h->nexthdr;
if (!IPV6_NH_OPT(nh))
goto found;
while ((o = packet_get_try(p, idx, offset, sizeof(*o), dlen))) {
nh = o->nexthdr;
hdrlen = (o->hdrlen + 1) * 8;
if (IPV6_NH_OPT(nh))
offset += hdrlen;
else
goto found;
}
return NULL;
found:
if (nh == 59)
return NULL;
*proto = nh;
return base + offset;
}
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