1 files changed, 87 insertions, 0 deletions
diff --git a/proto_ip_authentication_hdr.c b/proto_ip_authentication_hdr.c
new file mode 100644
index 0000000..2d5f57c
--- /dev/null
+++ b/proto_ip_authentication_hdr.c
@@ -0,0 +1,87 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Copyright 2012 Markus Amend <markus@netsniff-ng.org>, Deutsche Flugsicherung GmbH
+ * Subject to the GPL, version 2.
+ *
+ * IP Authentication Header described in RFC4302
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <netinet/in.h>    /* for ntohs() */
+
+#include "proto.h"
+#include "protos.h"
+#include "dissector_eth.h"
+#include "built_in.h"
+#include "pkt_buff.h"
+
+struct auth_hdr {
+	uint8_t h_next_header;
+	uint8_t h_payload_len;
+	uint16_t h_reserved;
+	uint32_t h_spi;
+	uint32_t h_snf;
+} __packed;
+
+static void auth_hdr(struct pkt_buff *pkt)
+{
+	ssize_t hdr_len;
+	size_t i;
+	struct auth_hdr *auth_ops;
+
+	auth_ops = (struct auth_hdr *) pkt_pull(pkt, sizeof(*auth_ops));
+	if (auth_ops == NULL)
+		return;
+	
+	hdr_len = (auth_ops->h_payload_len * 4) + 8;
+
+	tprintf(" [ Authentication Header ");
+	tprintf("NextHdr (%u), ", auth_ops->h_next_header);
+	if (hdr_len > pkt_len(pkt) || hdr_len < 0){
+		tprintf("HdrLen (%u, %zd Bytes %s), ",
+		      auth_ops->h_payload_len, hdr_len,
+		      colorize_start_full(black, red)
+		      "invalid" colorize_end());
+		      return;
+	}
+	tprintf("HdrLen (%u, %zd Bytes), ",auth_ops->h_payload_len, hdr_len);
+	tprintf("Reserved (0x%x), ", ntohs(auth_ops->h_reserved));
+	/* TODO
+	 * Upgrade for Extended (64-bit) Sequence Number
+	 * http://tools.ietf.org/html/rfc4302#section-2.5.1
+	 */
+	tprintf("SPI (0x%x), ", ntohl(auth_ops->h_spi));
+	tprintf("SNF (0x%x), ", ntohl(auth_ops->h_snf));
+	tprintf("ICV 0x");
+	for (i = sizeof(struct auth_hdr); i < hdr_len; i++)
+		tprintf("%02x", *pkt_pull(pkt, 1));
+	tprintf(" ]\n");
+
+	pkt_set_proto(pkt, &eth_lay3, auth_ops->h_next_header);
+}
+
+static void auth_hdr_less(struct pkt_buff *pkt)
+{
+  	ssize_t hdr_len;
+	struct auth_hdr *auth_ops;
+
+	auth_ops = (struct auth_hdr *) pkt_pull(pkt, sizeof(*auth_ops));
+	if (auth_ops == NULL)
+		return;
+	
+	hdr_len = (auth_ops->h_payload_len * 4) + 8;
+	if (hdr_len > pkt_len(pkt) || hdr_len < 0)
+		return;
+
+	tprintf(" AH");
+
+	pkt_pull(pkt, hdr_len - sizeof(*auth_ops));
+	pkt_set_proto(pkt, &eth_lay3, auth_ops->h_next_header);
+}
+
+struct protocol ip_auth_ops = {
+	.key = 0x33,
+	.print_full = auth_hdr,
+	.print_less = auth_hdr_less,
+};