user/ethdump: file per protocol, ethernet frame functions

1 files changed, 50 insertions, 0 deletions

diff --git a/src/user/app/ethdump/ipv4.c b/src/user/app/ethdump/ipv4.c
new file mode 100644
index 0000000..408e1df
--- /dev/null
+++ b/src/user/app/ethdump/ipv4.c
@@ -0,0 +1,50 @@
+#include "proto.h"
+#include "util.h"
+
+enum {
+	Version = 0,
+	HdrLen  = 0,
+	PktLen  = 2,
+	Id      = 4,
+	Proto   = 9,
+	SrcIP   = 12,
+	DestIP  = 16,
+};
+
+void ipv4_parse(const uint8_t *buf, size_t len) {
+	uint8_t version, headerlen, proto;
+	uint16_t packetlen, id;
+	uint32_t dest, src;
+
+	version   = buf[Version] >> 4;
+	if (version != 4) {
+		printf("bad IPv4 version %u\n", version);
+		return;
+	}
+	headerlen = (buf[HdrLen] & 0xf) * 4;
+	packetlen = nget16(buf + PktLen);
+	id        = nget16(buf + Id);
+	proto     = buf[Proto];
+	src  = nget32(buf + SrcIP);
+	dest = nget32(buf + DestIP);
+
+	// 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("id %u\n", id);
+	if (packetlen < headerlen) {
+		printf("headerlen too big\n");
+		return;
+	}
+	switch (proto) {
+		case 1:
+			printf("proto %u - icmp\n", proto);
+			icmp_parse(buf + headerlen, packetlen - headerlen);
+			break;
+		default:
+			printf("proto %u - unknown\n", proto);
+			break;
+	}
+}