trafgen: proto: Add ICMPv4 header generation

Support for generating ICMPv4 headers using the 'icmp4()/icmpv4()'
trafgen generation functions.

Fields supported:

    type      Set type field (default 0: Echo reply)
              Supported keywords: echorequest, echoreply
    code      Set code field (default 0)
    csum      Set checksum field (calculated by default)
    mtu	      Set mtu field for destination unreachable (default 0)
    seq	      Set sequence field (default 0)
    id        Set identifier field (default 0)
    addr      Set redirect address (default 0.0.0.0)

Example (send ping request):

  { icmpv4(echorequest, seq=1, id=1326) }

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
[tk: squash commits, consistency between functionality and docu]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

1 files changed, 42 insertions, 0 deletions

diff --git a/trafgen_l4.c b/trafgen_l4.c
index 886e2b2..c109675 100644
--- a/trafgen_l4.c
+++ b/trafgen_l4.c
@@ -138,6 +138,47 @@ static struct proto_hdr tcp_hdr = {
 	.packet_finish  = tcp_packet_finish,
 };
 
+static struct proto_field icmpv4_fields[] = {
+	{ .id = ICMPV4_TYPE,       .len = 1, .offset = 0 },
+	{ .id = ICMPV4_CODE,       .len = 1, .offset = 1 },
+	{ .id = ICMPV4_CSUM,       .len = 2, .offset = 2 },
+	/* Echo/Ping fields */
+	{ .id = ICMPV4_ID,         .len = 2, .offset = 4 },
+	{ .id = ICMPV4_SEQ,        .len = 2, .offset = 6 },
+	/* Redirect field */
+	{ .id = ICMPV4_REDIR_ADDR, .len = 4, .offset = 4 },
+	/* Next-hop MTU */
+	{ .id = ICMPV4_MTU,        .len = 2, .offset = 6 },
+};
+
+static void icmpv4_header_init(struct proto_hdr *hdr)
+{
+	proto_lower_default_add(hdr, PROTO_IP4);
+
+	proto_header_fields_add(hdr, icmpv4_fields, array_size(icmpv4_fields));
+}
+
+static void icmpv4_packet_finish(struct proto_hdr *hdr)
+{
+	struct packet *pkt;
+	uint16_t csum;
+
+	if (proto_field_is_set(hdr, ICMPV4_CSUM))
+		return;
+
+	pkt = current_packet();
+
+	csum = htons(calc_csum(proto_header_ptr(hdr), pkt->len - hdr->pkt_offset));
+	proto_field_set_u16(hdr, ICMPV4_CSUM, bswap_16(csum));
+}
+
+static struct proto_hdr icmpv4_hdr = {
+	.id		= PROTO_ICMP4,
+	.layer		= PROTO_L4,
+	.header_init	= icmpv4_header_init,
+	.packet_finish  = icmpv4_packet_finish,
+};
+
 static struct proto_field icmpv6_fields[] = {
 	{ .id = ICMPV6_TYPE, .len = 1, .offset = 0 },
 	{ .id = ICMPV6_CODE, .len = 1, .offset = 1 },
@@ -190,5 +231,6 @@ void protos_l4_init(void)
 {
 	proto_header_register(&udp_hdr);
 	proto_header_register(&tcp_hdr);
+	proto_header_register(&icmpv4_hdr);
 	proto_header_register(&icmpv6_hdr);
 }