1 files changed, 47 insertions, 12 deletions

diff --git a/src/user/app/ethdump/ipv4.c b/src/user/app/ethdump/ipv4.c
index 408e1df..c9b2df4 100644
--- a/src/user/app/ethdump/ipv4.c
+++ b/src/user/app/ethdump/ipv4.c
@@ -1,20 +1,23 @@
 #include "proto.h"
 #include "util.h"
+#include <stdlib.h>
 
 enum {
-	Version = 0,
-	HdrLen  = 0,
-	PktLen  = 2,
-	Id      = 4,
-	Proto   = 9,
-	SrcIP   = 12,
-	DestIP  = 16,
+	Version  = 0,
+	HdrLen   = 0,
+	PktLen   = 2,
+	Id       = 4,
+	TTL      = 8,
+	Proto    = 9,
+	Checksum = 10,
+	SrcIP    = 12,
+	DstIP    = 16,
 };
 
-void ipv4_parse(const uint8_t *buf, size_t len) {
+void ipv4_parse(const uint8_t *buf, size_t len, struct ethernet ether) {
 	uint8_t version, headerlen, proto;
 	uint16_t packetlen, id;
-	uint32_t dest, src;
+	uint32_t dst, src;
 
 	version   = buf[Version] >> 4;
 	if (version != 4) {
@@ -26,25 +29,57 @@ void ipv4_parse(const uint8_t *buf, size_t len) {
 	id        = nget16(buf + Id);
 	proto     = buf[Proto];
 	src  = nget32(buf + SrcIP);
-	dest = nget32(buf + DestIP);
+	dst = nget32(buf + DstIP);
 
 	// TODO checksum
 	// TODO fragmentation
 
 	printf("headerlen %u, packetlen %u (real %u), id %u\n", headerlen, packetlen, len, id);
-	printf("from %x to %x\n", src, dest);
+	printf("from %x to %x\n", src, dst);
 	printf("id %u\n", id);
 	if (packetlen < headerlen) {
 		printf("headerlen too big\n");
 		return;
 	}
+
+	struct ipv4 ip = (struct ipv4){
+		.e = ether,
+		.src = src,
+		.dst = dst,
+		.proto = proto,
+	};
+
 	switch (proto) {
 		case 1:
 			printf("proto %u - icmp\n", proto);
-			icmp_parse(buf + headerlen, packetlen - headerlen);
+			icmp_parse(buf + headerlen, packetlen - headerlen, ip);
 			break;
 		default:
 			printf("proto %u - unknown\n", proto);
 			break;
 	}
 }
+
+uint8_t *ipv4_start(size_t len, struct ipv4 ip) {
+	ip.e.type = ET_IPv4;
+	if (!ip.src) ip.src = state.ip;
+	if (!ip.e.dst && ip.dst == 0xFFFFFFFF)
+		ip.e.dst = &MAC_BROADCAST;
+
+	size_t hdrlen = 20;
+	uint8_t *pkt = ether_start(len + hdrlen, ip.e);
+	pkt[Version] = 0x40;
+	pkt[HdrLen] |= hdrlen / 4;
+	nput16(pkt + PktLen, len + hdrlen);
+	pkt[TTL] = 0xFF;
+	pkt[Proto] = ip.proto;
+	nput32(pkt + SrcIP, ip.src);
+	nput32(pkt + DstIP, ip.dst);
+
+	nput16(pkt + Checksum, ip_checksum(pkt, hdrlen));
+
+	return pkt + hdrlen;
+}
+void ipv4_finish(uint8_t *pkt) {
+	ether_finish(pkt - 20);
+}