Import upstream release 5.2.1

1 files changed, 289 insertions, 9 deletions

diff --git a/src/libipsec/ip_packet.c b/src/libipsec/ip_packet.c
index 181cb88db..0998efa9d 100644
--- a/src/libipsec/ip_packet.c
+++ b/src/libipsec/ip_packet.c
@@ -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
@@ -26,6 +26,33 @@
 #include <netinet/ip6.h>
 #endif
 
+/**
+ * TCP header, defined here because platforms disagree regarding member names
+ * and unfortunately Android does not define a variant with BSD names.
+ */
+struct tcphdr {
+	u_int16_t source;
+	u_int16_t dest;
+	u_int32_t seq;
+	u_int32_t ack_seq;
+	u_int16_t flags;
+	u_int16_t window;
+	u_int16_t check;
+	u_int16_t urg_ptr;
+} __attribute__((packed));
+
+/**
+ * UDP header, similar to the TCP header the system headers disagree on member
+ * names.  Linux uses a union and on Android we could define __FAVOR_BSD to get
+ * the BSD member names, but this is simpler and more consistent with the above.
+ */
+struct udphdr {
+	u_int16_t source;
+	u_int16_t dest;
+	u_int16_t len;
+	u_int16_t check;
+} __attribute__((packed));
+
 typedef struct private_ip_packet_t private_ip_packet_t;
 
 /**
@@ -54,6 +81,11 @@ struct private_ip_packet_t {
 	chunk_t packet;
 
 	/**
+	 * IP payload (points into packet)
+	 */
+	chunk_t payload;
+
+	/**
 	 * IP version
 	 */
 	u_int8_t version;
@@ -89,6 +121,12 @@ METHOD(ip_packet_t, get_encoding, chunk_t,
 	return this->packet;
 }
 
+METHOD(ip_packet_t, get_payload, chunk_t,
+	private_ip_packet_t *this)
+{
+	return this->payload;
+}
+
 METHOD(ip_packet_t, get_next_header, u_int8_t,
 	private_ip_packet_t *this)
 {
@@ -111,13 +149,57 @@ METHOD(ip_packet_t, destroy, void,
 }
 
 /**
+ * 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.
  */
 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;
+	chunk_t payload;
 
 	if (packet.len < 1)
 	{
@@ -141,11 +223,15 @@ ip_packet_t *ip_packet_create(chunk_t packet)
 			ip = (struct ip*)packet.ptr;
 			/* remove any RFC 4303 TFC extra padding */
 			packet.len = min(packet.len, untoh16(&ip->ip_len));
-
+			payload = chunk_skip(packet, ip->ip_hl * 4);
+			if (!parse_transport_header(payload, 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;
 		}
@@ -154,19 +240,25 @@ 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;
 			}
 			ip = (struct ip6_hdr*)packet.ptr;
 			/* remove any RFC 4303 TFC extra padding */
-			packet.len = min(packet.len, untoh16(&ip->ip6_plen));
-
+			packet.len = min(packet.len, 40 + untoh16(&ip->ip6_plen));
+			/* we only handle packets without extension headers, just skip the
+			 * basic IPv6 header */
+			payload = chunk_skip(packet, 40);
+			if (!parse_transport_header(payload, 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;
 		}
@@ -183,12 +275,14 @@ ip_packet_t *ip_packet_create(chunk_t packet)
 			.get_destination = _get_destination,
 			.get_next_header = _get_next_header,
 			.get_encoding = _get_encoding,
+			.get_payload = _get_payload,
 			.clone = _clone_,
 			.destroy = _destroy,
 		},
 		.src = src,
 		.dst = dst,
 		.packet = packet,
+		.payload = payload,
 		.version = version,
 		.next_header = next_header,
 	);
@@ -198,3 +292,189 @@ failed:
 	chunk_free(&packet);
 	return NULL;
 }
+
+/**
+ * Calculate the checksum for the pseudo IP header
+ */
+static u_int16_t pseudo_header_checksum(host_t *src, host_t *dst,
+										u_int8_t proto, chunk_t payload)
+{
+	switch (src->get_family(src))
+	{
+		case AF_INET:
+		{
+			struct __attribute__((packed)) {
+				u_int32_t src;
+				u_int32_t dst;
+				u_char zero;
+				u_char proto;
+				u_int16_t len;
+			} pseudo = {
+				.proto = proto,
+				.len = htons(payload.len),
+			};
+			memcpy(&pseudo.src, src->get_address(src).ptr,
+				   sizeof(pseudo.src));
+			memcpy(&pseudo.dst, dst->get_address(dst).ptr,
+				   sizeof(pseudo.dst));
+			return chunk_internet_checksum(chunk_from_thing(pseudo));
+		}
+		case AF_INET6:
+		{
+			struct __attribute__((packed)) {
+				u_char src[16];
+				u_char dst[16];
+				u_int32_t len;
+				u_char zero[3];
+				u_char next_header;
+			} pseudo = {
+				.next_header = proto,
+				.len = htons(payload.len),
+			};
+			memcpy(&pseudo.src, src->get_address(src).ptr,
+				   sizeof(pseudo.src));
+			memcpy(&pseudo.dst, dst->get_address(dst).ptr,
+				   sizeof(pseudo.dst));
+			return chunk_internet_checksum(chunk_from_thing(pseudo));
+		}
+	}
+	return 0xffff;
+}
+
+/**
+ * Apply transport ports and calculate header checksums
+ */
+static void fix_transport_header(host_t *src, host_t *dst, u_int8_t proto,
+								 chunk_t payload)
+{
+	u_int16_t sum = 0, sport, dport;
+
+	sport = src->get_port(src);
+	dport = dst->get_port(dst);
+
+	switch (proto)
+	{
+		case IPPROTO_UDP:
+		{
+			struct udphdr *udp;
+
+			if (payload.len < sizeof(*udp))
+			{
+				return;
+			}
+			udp = (struct udphdr*)payload.ptr;
+			if (sport != 0)
+			{
+				udp->source = htons(sport);
+			}
+			if (dport != 0)
+			{
+				udp->dest = htons(dport);
+			}
+			udp->check = 0;
+			sum = pseudo_header_checksum(src, dst, proto, payload);
+			udp->check = chunk_internet_checksum_inc(payload, sum);
+			break;
+		}
+		case IPPROTO_TCP:
+		{
+			struct tcphdr *tcp;
+
+			if (payload.len < sizeof(*tcp))
+			{
+				return;
+			}
+			tcp = (struct tcphdr*)payload.ptr;
+			if (sport != 0)
+			{
+				tcp->source = htons(sport);
+			}
+			if (dport != 0)
+			{
+				tcp->dest = htons(dport);
+			}
+			tcp->check = 0;
+			sum = pseudo_header_checksum(src, dst, proto, payload);
+			tcp->check = chunk_internet_checksum_inc(payload, sum);
+			break;
+		}
+		default:
+			break;
+	}
+}
+
+/**
+ * Described in header.
+ */
+ip_packet_t *ip_packet_create_from_data(host_t *src, host_t *dst,
+										u_int8_t next_header, chunk_t data)
+{
+	chunk_t packet;
+	int family;
+
+	family = src->get_family(src);
+	if (family != dst->get_family(dst))
+	{
+		DBG1(DBG_ESP, "address family does not match");
+		return NULL;
+	}
+
+	switch (family)
+	{
+		case AF_INET:
+		{
+			struct ip ip = {
+				.ip_v = 4,
+				.ip_hl = 5,
+				.ip_len = htons(20 + data.len),
+				.ip_ttl = 0x80,
+				.ip_p = next_header,
+			};
+			memcpy(&ip.ip_src, src->get_address(src).ptr, sizeof(ip.ip_src));
+			memcpy(&ip.ip_dst, dst->get_address(dst).ptr, sizeof(ip.ip_dst));
+			ip.ip_sum = chunk_internet_checksum(chunk_from_thing(ip));
+
+			packet = chunk_cat("cc", chunk_from_thing(ip), data);
+			fix_transport_header(src, dst, next_header, chunk_skip(packet, 20));
+			return ip_packet_create(packet);
+		}
+#ifdef HAVE_NETINET_IP6_H
+		case AF_INET6:
+		{
+			struct ip6_hdr ip = {
+				.ip6_flow = htonl(6),
+				.ip6_plen = htons(40 + data.len),
+				.ip6_nxt = next_header,
+				.ip6_hlim = 0x80,
+			};
+			memcpy(&ip.ip6_src, src->get_address(src).ptr, sizeof(ip.ip6_src));
+			memcpy(&ip.ip6_dst, dst->get_address(dst).ptr, sizeof(ip.ip6_dst));
+
+			packet = chunk_cat("cc", chunk_from_thing(ip), data);
+			fix_transport_header(src, dst, next_header, chunk_skip(packet, 40));
+			return ip_packet_create(packet);
+		}
+#endif /* HAVE_NETINET_IP6_H */
+		default:
+			DBG1(DBG_ESP, "unsupported address family");
+			return NULL;
+	}
+}
+
+/**
+ * Described in header.
+ */
+ip_packet_t *ip_packet_create_udp_from_data(host_t *src, host_t *dst,
+											chunk_t data)
+{
+	struct udphdr udp = {
+		.len = htons(8 + data.len),
+		.check = 0,
+	};
+	ip_packet_t *packet;
+
+	data = chunk_cat("cc", chunk_from_thing(udp), data);
+	packet = ip_packet_create_from_data(src, dst, IPPROTO_UDP, data);
+	chunk_free(&data);
+	return packet;
+}