1 files changed, 91 insertions, 0 deletions
diff --git a/test/packetdrill/udp_packet.c b/test/packetdrill/udp_packet.c
new file mode 100644
index 0000000..81c9187
--- /dev/null
+++ b/test/packetdrill/udp_packet.c
@@ -0,0 +1,91 @@
+/*
+ * 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 module for formatting UDP packets.
+ */
+
+#include "udp_packet.h"
+
+#include "ip_packet.h"
+#include "udp.h"
+
+struct packet *new_udp_packet(int address_family,
+			       enum direction_t direction,
+			       struct ip_info ip_info,
+			       u16 udp_payload_bytes,
+			       u16 src_port,
+			       u16 dst_port,
+			       char **error)
+{
+	struct packet *packet = NULL;  /* the newly-allocated result packet */
+	struct header *udp_header = NULL;  /* the UDP header info */
+	/* Calculate lengths in bytes of all sections of the packet */
+	const int ip_option_bytes = 0;
+	const int ip_header_bytes = (ip_header_min_len(address_family) +
+				     ip_option_bytes);
+	const int udp_header_bytes = sizeof(struct udp);
+	const int ip_bytes =
+		 ip_header_bytes + udp_header_bytes + udp_payload_bytes;
+
+	/* Sanity-check all the various lengths */
+	if (ip_option_bytes & 0x3) {
+		asprintf(error, "IP options are not padded correctly "
+			 "to ensure IP header is a multiple of 4 bytes: "
+			 "%d excess bytes", ip_option_bytes & 0x3);
+		return NULL;
+	}
+	assert((udp_header_bytes & 0x3) == 0);
+	assert((ip_header_bytes & 0x3) == 0);
+
+	if (ip_bytes > MAX_UDP_DATAGRAM_BYTES) {
+		asprintf(error, "UDP datagram too large");
+		return NULL;
+	}
+
+	/* Allocate and zero out a packet object of the desired size */
+	packet = packet_new(ip_bytes);
+	memset(packet->buffer, 0, ip_bytes);
+
+	packet->direction = direction;
+	packet->flags = 0;
+	packet->tos_chk = ip_info.tos.check;
+
+	/* Set IP header fields */
+	set_packet_ip_header(packet, address_family, ip_bytes,
+			     ip_info.tos.value, ip_info.flow_label,
+			     ip_info.ttl, IPPROTO_UDP);
+
+	udp_header = packet_append_header(packet, HEADER_UDP,
+					  sizeof(struct udp));
+	udp_header->total_bytes = udp_header_bytes + udp_payload_bytes;
+
+	/* Find the start of UDP section of the packet */
+	packet->udp = (struct udp *) (ip_start(packet) + ip_header_bytes);
+
+	/* Set UDP header fields */
+	packet->udp->src_port	= htons(src_port);
+	packet->udp->dst_port	= htons(dst_port);
+	packet->udp->len	= htons(udp_header_bytes + udp_payload_bytes);
+	packet->udp->check	= 0;
+
+	packet->ip_bytes = ip_bytes;
+	return packet;
+}