1 files changed, 303 insertions, 0 deletions

diff --git a/test/packetdrill/packet_to_string.c b/test/packetdrill/packet_to_string.c
new file mode 100644
index 0000000..1fd90b2
--- /dev/null
+++ b/test/packetdrill/packet_to_string.c
@@ -0,0 +1,303 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+/*
+ * Author: ncardwell@google.com (Neal Cardwell)
+ *
+ * Implementation for generating human-readable representations of IP
+ * packets.
+ */
+
+#include "packet_to_string.h"
+
+#include <stdlib.h>
+#include "socket.h"
+#include "tcp_options_to_string.h"
+
+static void endpoints_to_string(FILE *s, const struct packet *packet)
+{
+	char src_string[ADDR_STR_LEN];
+	char dst_string[ADDR_STR_LEN];
+	struct tuple tuple;
+
+	get_packet_tuple(packet, &tuple);
+
+	fprintf(s, "%s:%u > %s:%u",
+		ip_to_string(&tuple.src.ip, src_string), ntohs(tuple.src.port),
+		ip_to_string(&tuple.dst.ip, dst_string), ntohs(tuple.dst.port));
+}
+
+static void packet_buffer_to_string(FILE *s, struct packet *packet)
+{
+	char *hex = NULL;
+	hex_dump(packet->buffer, packet_end(packet) - packet->buffer, &hex);
+	fputc('\n', s);
+	fprintf(s, "%s", hex);
+	free(hex);
+}
+
+static int ipv4_header_to_string(FILE *s, struct packet *packet, int layer,
+				 enum dump_format_t format, char **error)
+{
+	char src_string[ADDR_STR_LEN];
+	char dst_string[ADDR_STR_LEN];
+	struct ip_address src_ip, dst_ip;
+	const struct ipv4 *ipv4 = packet->headers[layer].h.ipv4;
+
+	ip_from_ipv4(&ipv4->src_ip, &src_ip);
+	ip_from_ipv4(&ipv4->dst_ip, &dst_ip);
+
+	fprintf(s, "ipv4 %s > %s: ",
+		ip_to_string(&src_ip, src_string),
+		ip_to_string(&dst_ip, dst_string));
+
+	return STATUS_OK;
+}
+
+static int ipv6_header_to_string(FILE *s, struct packet *packet, int layer,
+				 enum dump_format_t format, char **error)
+{
+	char src_string[ADDR_STR_LEN];
+	char dst_string[ADDR_STR_LEN];
+	struct ip_address src_ip, dst_ip;
+	const struct ipv6 *ipv6 = packet->headers[layer].h.ipv6;
+
+	ip_from_ipv6(&ipv6->src_ip, &src_ip);
+	ip_from_ipv6(&ipv6->dst_ip, &dst_ip);
+
+	fprintf(s, "ipv6 %s > %s: ",
+		ip_to_string(&src_ip, src_string),
+		ip_to_string(&dst_ip, dst_string));
+
+	return STATUS_OK;
+}
+
+static int gre_header_to_string(FILE *s, struct packet *packet, int layer,
+				enum dump_format_t format, char **error)
+{
+	const struct gre *gre = packet->headers[layer].h.gre;
+	int i = 0;
+
+	fprintf(s, "gre flags 0x%x proto 0x%04x",
+		ntohs(gre->flags),
+		ntohs(gre->proto));
+
+	if (gre->has_checksum || gre->has_routing) {
+		fprintf(s, " sum 0x%x off 0x%x",
+			ntohs(gre->be16[0]),
+			ntohs(gre->be16[1]));
+		i++;
+	}
+
+	if (gre->has_key) {
+		fprintf(s, " key 0x%x", ntohl(gre->be32[i]));
+		i++;
+	}
+
+	if (gre->has_seq) {
+		fprintf(s, " seq 0x%x", ntohl(gre->be32[i]));
+		i++;
+	}
+
+	fprintf(s, ": ");
+	return STATUS_OK;
+}
+
+static int mpls_header_to_string(FILE *s, struct packet *packet, int layer,
+				 enum dump_format_t format, char **error)
+{
+	struct header *header = &packet->headers[layer];
+	int num_entries = header->header_bytes / sizeof(struct mpls);
+	int i = 0;
+
+	fprintf(s, "mpls");
+
+	for (i = 0; i < num_entries; ++i) {
+		const struct mpls *mpls = header->h.mpls + i;
+
+		fprintf(s, " (label %u, tc %u,%s ttl %u)",
+			mpls_entry_label(mpls),
+			mpls_entry_tc(mpls),
+			mpls_entry_stack(mpls) ? " [S]," : "",
+			mpls_entry_ttl(mpls));
+	}
+
+	fprintf(s, ": ");
+	return STATUS_OK;
+}
+
+/* Print a string representation of the TCP packet:
+ *  direction opt_ip_info flags seq ack window tcp_options
+ */
+static int tcp_packet_to_string(FILE *s, struct packet *packet,
+				enum dump_format_t format, char **error)
+{
+	int result = STATUS_OK;       /* return value */
+
+	if ((format == DUMP_FULL) || (format == DUMP_VERBOSE)) {
+		endpoints_to_string(s, packet);
+		fputc(' ', s);
+	}
+
+
+	/* We print flags in the same order as tcpdump 4.1.1. */
+	if (packet->tcp->fin)
+		fputc('F', s);
+	if (packet->tcp->syn)
+		fputc('S', s);
+	if (packet->tcp->rst)
+		fputc('R', s);
+	if (packet->tcp->psh)
+		fputc('P', s);
+	if (packet->tcp->ack)
+		fputc('.', s);
+	if (packet->tcp->urg)
+		fputc('U', s);
+	if (packet->tcp->ece)
+		fputc('E', s);   /* ECN *E*cho sent (ECN) */
+	if (packet->tcp->cwr)
+		fputc('W', s);   /* Congestion *W*indow reduced (ECN) */
+
+	fprintf(s, " %u:%u(%u) ",
+		ntohl(packet->tcp->seq),
+		ntohl(packet->tcp->seq) + packet_payload_len(packet),
+		packet_payload_len(packet));
+
+	if (packet->tcp->ack)
+		fprintf(s, "ack %u ", ntohl(packet->tcp->ack_seq));
+
+	if (!(packet->flags & FLAG_WIN_NOCHECK))
+		fprintf(s, "win %u ", ntohs(packet->tcp->window));
+
+	if (packet_tcp_options_len(packet) > 0) {
+		char *tcp_options = NULL;
+		if (tcp_options_to_string(packet, &tcp_options, error))
+			result = STATUS_ERR;
+		else
+			fprintf(s, "<%s>", tcp_options);
+		free(tcp_options);
+	}
+
+	if (format == DUMP_VERBOSE)
+		packet_buffer_to_string(s, packet);
+
+	return result;
+}
+
+static int udp_packet_to_string(FILE *s, struct packet *packet,
+				enum dump_format_t format, char **error)
+{
+	int result = STATUS_OK;       /* return value */
+
+	if ((format == DUMP_FULL) || (format == DUMP_VERBOSE)) {
+		endpoints_to_string(s, packet);
+		fputc(' ', s);
+	}
+
+	fprintf(s, "udp (%u)", packet_payload_len(packet));
+
+	if (format == DUMP_VERBOSE)
+		packet_buffer_to_string(s, packet);
+
+	return result;
+}
+
+static int icmpv4_packet_to_string(FILE *s, struct packet *packet,
+				   enum dump_format_t format, char **error)
+{
+	fprintf(s, "icmpv4");
+	/* TODO(ncardwell): print type, code; use tables from icmp_packet.c */
+	return STATUS_OK;
+}
+
+static int icmpv6_packet_to_string(FILE *s, struct packet *packet,
+				   enum dump_format_t format, char **error)
+{
+	fprintf(s, "icmpv6");
+	/* TODO(ncardwell): print type, code; use tables from icmp_packet.c */
+	return STATUS_OK;
+}
+
+typedef int (*header_to_string_func)(FILE *s, struct packet *packet, int layer,
+				     enum dump_format_t format, char **error);
+
+static int encap_header_to_string(FILE *s, struct packet *packet, int layer,
+				  enum dump_format_t format, char **error)
+{
+	header_to_string_func printers[HEADER_NUM_TYPES] = {
+		[HEADER_IPV4]	= ipv4_header_to_string,
+		[HEADER_IPV6]	= ipv6_header_to_string,
+		[HEADER_GRE]	= gre_header_to_string,
+		[HEADER_MPLS]	= mpls_header_to_string,
+	};
+	header_to_string_func printer = NULL;
+	enum header_t type = packet->headers[layer].type;
+
+	assert(type > HEADER_NONE);
+	assert(type < HEADER_NUM_TYPES);
+	printer = printers[type];
+	assert(printer != NULL);
+	return printer(s, packet, layer, format, error);
+}
+
+
+int packet_to_string(struct packet *packet,
+		     enum dump_format_t format,
+		     char **ascii_string, char **error)
+{
+	assert(packet != NULL);
+	int result = STATUS_ERR;       /* return value */
+	size_t size = 0;
+	FILE *s = open_memstream(ascii_string, &size);  /* output string */
+	int i;
+	int header_count = packet_header_count(packet);
+
+	/* Print any encapsulation headers preceding layer 3 and 4 headers. */
+	for (i = 0; i < header_count - 2; ++i) {
+		if (packet->headers[i].type == HEADER_NONE)
+			break;
+		if (encap_header_to_string(s, packet, i, format, error))
+			goto out;
+	}
+
+	if ((packet->ipv4 == NULL) && (packet->ipv6 == NULL)) {
+		fprintf(s, "[NO IP HEADER]");
+	} else {
+		if (packet->tcp != NULL) {
+			if (tcp_packet_to_string(s, packet, format, error))
+				goto out;
+		} else if (packet->udp != NULL) {
+			if (udp_packet_to_string(s, packet, format, error))
+				goto out;
+		} else if (packet->icmpv4 != NULL) {
+			if (icmpv4_packet_to_string(s, packet, format, error))
+				goto out;
+		} else if (packet->icmpv6 != NULL) {
+			if (icmpv6_packet_to_string(s, packet, format, error))
+				goto out;
+		} else {
+			fprintf(s, "[NO TCP OR ICMP HEADER]");
+		}
+	}
+
+	result = STATUS_OK;
+
+out:
+	fclose(s);
+	return result;
+}