From 7483470f4508a2a56492b00b1ccde0f24c14a4e2 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 27 Aug 2022 15:46:58 +0200
Subject: user/netstack: don't respond to RST

---
 src/user/app/netstack/netstack.c |  3 +++
 src/user/app/netstack/tcp.c      | 36 +++++++++++++++++++-----------------
 2 files changed, 22 insertions(+), 17 deletions(-)

(limited to 'src')

diff --git a/src/user/app/netstack/netstack.c b/src/user/app/netstack/netstack.c
index 75a5162..cc5247b 100644
--- a/src/user/app/netstack/netstack.c
+++ b/src/user/app/netstack/netstack.c
@@ -25,7 +25,10 @@ void network_thread(void *arg) { (void)arg;
 
 void fs_thread(void *arg);
 
+__attribute__((visibility("hidden")))
+extern char _image_base[];
 int main(int argc, char **argv) {
+	eprintf("0x%x", _image_base);
 	if (argc < 4) {
 		eprintf("usage: netstack iface ip gateway");
 		return 1;
diff --git a/src/user/app/netstack/tcp.c b/src/user/app/netstack/tcp.c
index dd6d121..daa728f 100644
--- a/src/user/app/netstack/tcp.c
+++ b/src/user/app/netstack/tcp.c
@@ -245,22 +245,24 @@ void tcp_parse(const uint8_t *buf, size_t len, struct ipv4 ip) {
 		}
 	}
 
-	uint8_t *pkt = malloc(MinHdr);
-	memset(pkt, 0, MinHdr);
-	nput16(pkt + SrcPort, dstport);
-	nput16(pkt + DstPort, srcport);
-	nput32(pkt + Seq, acknum);
-	nput32(pkt + AckNum, seq + 1);
-	uint16_t pktflags = FlagRST | FlagACK;
-	pktflags |= (MinHdr / 4) << 12;
-	nput16(pkt + Flags, pktflags);
-	nput16(pkt + Checksum, ip_checksumphdr(pkt, MinHdr, ip.src, ip.dst, 6));
+	if ((flags & FlagRST) == 0) {
+		uint8_t *pkt = malloc(MinHdr);
+		memset(pkt, 0, MinHdr);
+		nput16(pkt + SrcPort, dstport);
+		nput16(pkt + DstPort, srcport);
+		nput32(pkt + Seq, acknum);
+		nput32(pkt + AckNum, seq + 1);
+		uint16_t pktflags = FlagRST | FlagACK;
+		pktflags |= (MinHdr / 4) << 12;
+		nput16(pkt + Flags, pktflags);
+		nput16(pkt + Checksum, ip_checksumphdr(pkt, MinHdr, ip.src, ip.dst, 6));
 
-	ipv4_send(pkt, MinHdr, (struct ipv4){
-		.proto = 6,
-		.src = ip.dst,
-		.dst = ip.src,
-		.e.dst = ip.e.src,
-	});
-	free(pkt);
+		ipv4_send(pkt, MinHdr, (struct ipv4){
+			.proto = 6,
+			.src = ip.dst,
+			.dst = ip.src,
+			.e.dst = ip.e.src,
+		});
+		free(pkt);
+	}
 }
-- 
cgit v1.2.3