quic: ignore EMSGSIZE on receive

Some OSes (Linux, macOS, more?) will generate an EMSGSIZE socket error
on the next recv all after receiving an ICMP Packet Too Big on an
unconnected UDP socket.

These can be safely ignored as QUIC's DPLPMTUD uses MTU probes that do
not rely on receiving ICMP packets.

Closes #18505

diff --git a/lib/vquic/vquic.c b/lib/vquic/vquic.c
index 647450a29ba4626618d049c55e172fef640bab60..3a0ac872383f8df42d746c55245083a5d77bdc46 100644 (file)
--- a/lib/vquic/vquic.c
+++ b/lib/vquic/vquic.c
@@ -404,7 +404,7 @@ static CURLcode recvmmsg_packets(struct Curl_cfilter *cf,
     }
 
     while((mcount = recvmmsg(qctx->sockfd, mmsg, n, 0, NULL)) == -1 &&
-          SOCKERRNO == SOCKEINTR)
+          (SOCKERRNO == SOCKEINTR || SOCKERRNO == SOCKEMSGSIZE))
       ;
     if(mcount == -1) {
       if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {
@@ -420,7 +420,7 @@ static CURLcode recvmmsg_packets(struct Curl_cfilter *cf,
         goto out;
       }
       Curl_strerror(SOCKERRNO, errstr, sizeof(errstr));
-      failf(data, "QUIC: recvmsg() unexpectedly returned %d (errno=%d; %s)",
+      failf(data, "QUIC: recvmmsg() unexpectedly returned %d (errno=%d; %s)",
                   mcount, SOCKERRNO, errstr);
       result = CURLE_RECV_ERROR;
       goto out;
@@ -497,7 +497,7 @@ static CURLcode recvmsg_packets(struct Curl_cfilter *cf,
     msg.msg_controllen = sizeof(msg_ctrl);
 
     while((nread = recvmsg(qctx->sockfd, &msg, 0)) == -1 &&
-          SOCKERRNO == SOCKEINTR)
+          (SOCKERRNO == SOCKEINTR || SOCKERRNO == SOCKEMSGSIZE))
       ;
     if(nread == -1) {
       if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {
@@ -571,7 +571,7 @@ static CURLcode recvfrom_packets(struct Curl_cfilter *cf,
     while((nread = recvfrom(qctx->sockfd, (char *)buf, bufsize, 0,
                             (struct sockaddr *)&remote_addr,
                             &remote_addrlen)) == -1 &&
-          SOCKERRNO == SOCKEINTR)
+          (SOCKERRNO == SOCKEINTR || SOCKERRNO == SOCKEMSGSIZE))
       ;
     if(nread == -1) {
       if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {