From ef51e071db7b371786def6b2ea30410663ed8409 Mon Sep 17 00:00:00 2001
From: Neal Cardwell <ncardwell@google.com>
Date: Fri, 22 Nov 2013 11:57:25 -0500
Subject: [PATCH] net-test: packetdrill MPLS support: parse MPLS label stacks
in packets
Code to parse on-the-wire packets using an encapsulation layer that is an
MPLS label stack.
Change-Id: I62585d491303cd8bd85c8afe5b652c4f1be572d9
---
gtests/net/packetdrill/packet_parser.c | 72 ++++++++++++++++++++++----
1 file changed, 61 insertions(+), 11 deletions(-)
diff --git a/gtests/net/packetdrill/packet_parser.c b/gtests/net/packetdrill/packet_parser.c
index 6001c800..697c5aa1 100644
--- a/gtests/net/packetdrill/packet_parser.c
+++ b/gtests/net/packetdrill/packet_parser.c
@@ -48,6 +48,8 @@ static int parse_ipv4(struct packet *packet, u8 *header_start, u8 *packet_end,
char **error);
static int parse_ipv6(struct packet *packet, u8 *header_start, u8 *packet_end,
char **error);
+static int parse_mpls(struct packet *packet, u8 *header_start, u8 *packet_end,
+ char **error);
static int parse_layer3_packet_by_proto(struct packet *packet,
u16 proto, u8 *header_start,
u8 *packet_end, char **error);
@@ -55,12 +57,11 @@ static int parse_layer4(struct packet *packet, u8 *header_start,
int layer4_protocol, int layer4_bytes,
u8 *packet_end, bool *is_inner, char **error);
-static int parse_layer2_packet(struct packet *packet, int in_bytes,
- char **error)
+static int parse_layer2_packet(struct packet *packet,
+ u8 *header_start, u8 *packet_end,
+ char **error)
{
- u8 *p = packet->buffer;
- /* Note that packet_end points to the byte beyond the end of packet. */
- u8 *packet_end = packet->buffer + in_bytes;
+ u8 *p = header_start;
struct ether_header *ether = NULL;
/* Find Ethernet header */
@@ -122,6 +123,9 @@ static int parse_layer3_packet_by_proto(struct packet *packet,
asprintf(error, "Bad IP version for ETHERTYPE_IPV6");
goto error_out;
}
+ } else if ((proto == ETHERTYPE_MPLS_UC) ||
+ (proto == ETHERTYPE_MPLS_MC)) {
+ return parse_mpls(packet, p, packet_end, error);
} else {
return PACKET_UNKNOWN_L4;
}
@@ -130,12 +134,12 @@ error_out:
return PACKET_BAD;
}
-static int parse_layer3_packet(struct packet *packet, int in_bytes,
- char **error)
+static int parse_layer3_packet(struct packet *packet,
+ u8 *header_start, u8 *packet_end,
+ char **error)
{
- u8 *p = packet->buffer;
+ u8 *p = header_start;
/* Note that packet_end points to the byte beyond the end of packet. */
- u8 *packet_end = packet->buffer + in_bytes;
struct ipv4 *ip = NULL;
/* Examine IPv4/IPv6 header. */
@@ -164,11 +168,16 @@ int parse_packet(struct packet *packet, int in_bytes,
char *message = NULL; /* human-readable error summary */
char *hex = NULL; /* hex dump of bad packet */
enum packet_parse_result_t result = PACKET_BAD;
+ u8 *header_start = packet->buffer;
+ /* packet_end points to the byte beyond the end of packet. */
+ u8 *packet_end = packet->buffer + in_bytes;
if (layer == PACKET_LAYER_2_ETHERNET)
- result = parse_layer2_packet(packet, in_bytes, error);
+ result = parse_layer2_packet(packet, header_start, packet_end,
+ error);
else if (layer == PACKET_LAYER_3_IP)
- result = parse_layer3_packet(packet, in_bytes, error);
+ result = parse_layer3_packet(packet, header_start, packet_end,
+ error);
else
assert(!"bad layer");
@@ -483,6 +492,47 @@ error_out:
return PACKET_BAD;
}
+int parse_mpls(struct packet *packet, u8 *header_start, u8 *packet_end,
+ char **error)
+{
+ struct header *mpls_header = NULL;
+ u8 *p = header_start;
+ int mpls_header_bytes = 0;
+ int mpls_total_bytes = packet_end - p;
+ bool is_stack_bottom = false;
+
+ do {
+ struct mpls *mpls_entry = (struct mpls *)(p);
+
+ if (p + sizeof(struct mpls) > packet_end) {
+ asprintf(error, "MPLS stack entry overflows packet");
+ goto error_out;
+ }
+
+ is_stack_bottom = mpls_entry_stack(mpls_entry);
+
+ p += sizeof(struct mpls);
+ mpls_header_bytes += sizeof(struct mpls);
+ } while (!is_stack_bottom && p < packet_end);
+
+ assert(mpls_header_bytes <= mpls_total_bytes);
+
+ mpls_header = packet_append_header(packet, HEADER_MPLS,
+ mpls_header_bytes);
+ if (mpls_header == NULL) {
+ asprintf(error, "Too many nested headers at MPLS header");
+ goto error_out;
+ }
+ mpls_header->total_bytes = mpls_total_bytes;
+
+ /* Move on to the header inside the MPLS label stack. */
+ assert(p <= packet_end);
+ return parse_layer3_packet(packet, p, packet_end, error);
+
+error_out:
+ return PACKET_BAD;
+}
+
static int parse_layer4(struct packet *packet, u8 *layer4_start,
int layer4_protocol, int layer4_bytes,
u8 *packet_end, bool *is_inner, char **error)
--
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