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