X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=slip.c;h=aed2551de70d2d695ec1ef99e04081923227dabf;hb=ab62c3ed691a3a6a1ce3f027f50a942c8397b063;hp=d8f1a17113f4cd20b8711617f684c07a1f1f159a;hpb=993db2a680648967ff59128c1aa003b9e87c6824;p=secnet.git

diff --git a/slip.c b/slip.c
index d8f1a17..aed2551 100644
--- a/slip.c
+++ b/slip.c
@@ -79,6 +79,9 @@ static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
 	int outputchr;
 	enum { OUTPUT_END = 256, OUTPUT_NOTHING = 257 };
 
+	if (!st->buff->size)
+	    buffer_init(st->buff,calculate_max_start_pad());
+
 	if (st->pending_esc) {
 	    st->pending_esc=False;
 	    switch(buf[i]) {
@@ -115,7 +118,7 @@ static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
 	if (st->ignoring_packet) {
 	    if (outputchr == OUTPUT_END) {
 		st->ignoring_packet=False;
-		buffer_init(st->buff,st->nl.max_start_pad);
+		st->buff->size=0;
 	    }
 	} else {
 	    if (outputchr == OUTPUT_END) {
@@ -123,7 +126,7 @@ static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
 		    st->netlink_to_tunnel(&st->nl,st->buff);
 		    BUF_ALLOC(st->buff,"userv_afterpoll");
 		}
-		buffer_init(st->buff,st->nl.max_start_pad);
+		st->buff->size=0;
 	    } else if (outputchr != OUTPUT_NOTHING) {
 		if (st->buff->size < st->buff->len) {
 		    buf_append_uint8(st->buff,outputchr);
@@ -210,6 +213,14 @@ static void userv_deliver_to_kernel(void *sst, struct buffer_if *buf)
 {
     struct userv *st=sst;
 
+    if (buf->size > st->slip.nl.mtu) {
+	Message(M_ERR,"%s: packet of size %"PRIu32" exceeds mtu %"PRIu32":"
+		" cannot be injected into kernel, dropped\n",
+		st->slip.nl.name, buf->size, st->slip.nl.mtu);
+	BUF_FREE(buf);
+	return;
+    }
+
     slip_stuff(&st->slip,buf,st->txfd);
 }
 
@@ -230,7 +241,8 @@ static void userv_userv_callback(void *sst, pid_t pid, int status)
 	    fatal("%s: userv exited unexpectedly: uncaught signal %d",
 		  st->slip.nl.name,WTERMSIG(status));
 	} else {
-	    fatal("%s: userv stopped unexpectedly");
+	    fatal("%s: userv stopped unexpectedly",
+		  st->slip.nl.name);
 	}
     }
     Message(M_WARNING,"%s: userv subprocess died with status %d\n",