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ip_packet: Parse ports from TCP and UDP headers

This commit is contained in:
Tobias Brunner 2014-07-14 17:33:17 +02:00
parent 32109a535f
commit a10eb93566
1 changed files with 63 additions and 7 deletions
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70
src/libipsec/ip_packet.c
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@ -1,5 +1,5 @@
/*
* Copyright (C) 2012 Tobias Brunner
* Copyright (C) 2012-2014 Tobias Brunner
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
@ -22,6 +22,8 @@
#include <sys/types.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>
#ifdef HAVE_NETINET_IP6_H
#include <netinet/ip6.h>
#endif
@ -110,6 +112,48 @@ METHOD(ip_packet_t, destroy, void,
free(this);
}
/**
* Parse transport protocol header
*/
static bool parse_transport_header(chunk_t packet, u_int8_t proto,
u_int16_t *sport, u_int16_t *dport)
{
switch (proto)
{
case IPPROTO_UDP:
{
struct udphdr *udp;
if (packet.len < sizeof(*udp))
{
DBG1(DBG_ESP, "UDP packet too short");
return FALSE;
}
udp = (struct udphdr*)packet.ptr;
*sport = ntohs(udp->source);
*dport = ntohs(udp->dest);
break;
}
case IPPROTO_TCP:
{
struct tcphdr *tcp;
if (packet.len < sizeof(*tcp))
{
DBG1(DBG_ESP, "TCP packet too short");
return FALSE;
}
tcp = (struct tcphdr*)packet.ptr;
*sport = ntohs(tcp->source);
*dport = ntohs(tcp->dest);
break;
}
default:
break;
}
return TRUE;
}
/**
* Described in header.
*/
@ -117,6 +161,7 @@ ip_packet_t *ip_packet_create(chunk_t packet)
{
private_ip_packet_t *this;
u_int8_t version, next_header;
u_int16_t sport = 0, dport = 0;
host_t *src, *dst;
if (packet.len < 1)
@ -142,10 +187,15 @@ ip_packet_t *ip_packet_create(chunk_t packet)
/* remove any RFC 4303 TFC extra padding */
packet.len = min(packet.len, untoh16(&ip->ip_len));
if (!parse_transport_header(chunk_skip(packet, ip->ip_hl * 4),
ip->ip_p, &sport, &dport))
{
goto failed;
}
src = host_create_from_chunk(AF_INET,
chunk_from_thing(ip->ip_src), 0);
chunk_from_thing(ip->ip_src), sport);
dst = host_create_from_chunk(AF_INET,
chunk_from_thing(ip->ip_dst), 0);
chunk_from_thing(ip->ip_dst), dport);
next_header = ip->ip_p;
break;
}
@ -154,7 +204,7 @@ ip_packet_t *ip_packet_create(chunk_t packet)
{
struct ip6_hdr *ip;
if (packet.len < sizeof(struct ip6_hdr))
if (packet.len < sizeof(*ip))
{
DBG1(DBG_ESP, "IPv6 packet too short");
goto failed;
@ -162,11 +212,17 @@ ip_packet_t *ip_packet_create(chunk_t packet)
ip = (struct ip6_hdr*)packet.ptr;
/* remove any RFC 4303 TFC extra padding */
packet.len = min(packet.len, untoh16(&ip->ip6_plen));
/* we only handle packets without extension headers, just skip the
* basic IPv6 header */
if (!parse_transport_header(chunk_skip(packet, 40), ip->ip6_nxt,
&sport, &dport))
{
goto failed;
}
src = host_create_from_chunk(AF_INET6,
chunk_from_thing(ip->ip6_src), 0);
chunk_from_thing(ip->ip6_src), sport);
dst = host_create_from_chunk(AF_INET6,
chunk_from_thing(ip->ip6_dst), 0);
chunk_from_thing(ip->ip6_dst), dport);
next_header = ip->ip6_nxt;
break;
}