user/netstack: ARP requests

3 files changed, 45 insertions, 1 deletions

diff --git a/src/user/app/netstack/arp.c b/src/user/app/netstack/arp.c
index 9e292b3..6c230b3 100644
--- a/src/user/app/netstack/arp.c
+++ b/src/user/app/netstack/arp.c
@@ -46,7 +46,7 @@ void arp_parse(const uint8_t *buf, size_t len) {
 				.dst = (void*)(buf + SrcMAC),
 				.type = ET_ARP,
 			});
-			nput16(pkt + HdrType, 1);
+			nput16(pkt + HdrType, HdrTypeEther);
 			nput16(pkt + ProtoType, ET_IPv4);
 			pkt[HdrALen] = 6;
 			pkt[ProtoALen] = 4;
@@ -59,6 +59,30 @@ void arp_parse(const uint8_t *buf, size_t len) {
 	}
 }
 
+void arp_request(uint32_t ip) {
+	enum {
+		SrcMAC =  8,
+		SrcIP  = 14,
+		DstMAC = 18,
+		DstIP  = 24,
+	};
+	uint8_t *pkt = ether_start(28, (struct ethernet){
+		.src = &state.mac,
+		.dst = &MAC_BROADCAST,
+		.type = ET_ARP,
+	});
+	nput16(pkt + HdrType, HdrTypeEther);
+	nput16(pkt + ProtoType, ET_IPv4);
+	pkt[HdrALen] = 6;
+	pkt[ProtoALen] = 4;
+	nput16(pkt + Operation, OpReq);
+	memcpy(pkt + SrcMAC, state.mac, 6);
+	nput32(pkt + SrcIP, state.ip);
+	memcpy(pkt + DstMAC, &MAC_BROADCAST, 6);
+	nput32(pkt + DstIP, ip);
+	ether_finish(pkt);
+}
+
 static void arpcache_put(uint32_t ip, mac_t mac) {
 	for (struct arpc *iter = arpcache; iter; iter = iter->next) {
 		if (memcmp(iter->mac, mac, 6) == 0) {
@@ -110,3 +134,18 @@ void arp_fsread(handle_t h, long offset) {
 err:
 	_syscall_fs_respond(h, NULL, -1, 0);
 }
+
+long arp_fswrite(const char *buf, long len, long offset) {
+	if (offset != -1) return -1;
+	uint32_t ip;
+	char tmp[16];
+	size_t iplen = len < 15 ? len : 15;
+	memcpy(tmp, buf, iplen);
+	tmp[iplen] = '\0';
+	if (ip_parse(tmp, &ip) < 0) {
+		return -1;
+	} else {
+		arp_request(ip);
+		return len;
+	}
+}
diff --git a/src/user/app/netstack/fs.c b/src/user/app/netstack/fs.c
index 9f40ef8..cbead8f 100644
--- a/src/user/app/netstack/fs.c
+++ b/src/user/app/netstack/fs.c
@@ -294,6 +294,9 @@ void fs_thread(void *arg) { (void)arg;
 						udpc_send(h->udp.c, buf, res.len);
 						_syscall_fs_respond(reqh, NULL, res.len, 0);
 						break;
+					case H_ARP:
+						_syscall_fs_respond(reqh, NULL, arp_fswrite(buf, res.len, res.offset), 0);
+						break;
 					default:
 						_syscall_fs_respond(reqh, NULL, -1, 0);
 				}
diff --git a/src/user/app/netstack/proto.h b/src/user/app/netstack/proto.h
index 30ff864..72a4fca 100644
--- a/src/user/app/netstack/proto.h
+++ b/src/user/app/netstack/proto.h
@@ -56,9 +56,11 @@ struct ethq {
 extern struct ethq *ether_queue;
 
 void arp_parse(const uint8_t *buf, size_t len);
+void arp_request(uint32_t ip);
 /* 0 on success, -1 on failure */
 int arpcache_get(uint32_t ip, mac_t *mac);
 void arp_fsread(handle_t h, long offset);
+long arp_fswrite(const char *buf, long len, long offset);
 
 void icmp_parse(const uint8_t *buf, size_t len, struct ipv4 ip);
 void icmp_send(const void *payload, size_t len, struct icmp i);