libsystemd-network: ignore -ENETDOWN or friends in recv()

And this makes most errors in io events ignored.

1 files changed, 23 insertions, 18 deletions

diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 14cbde133f..16574d28c7 100644
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -1930,13 +1930,13 @@ static int client_receive_message_udp(
         assert(client);
 
         buflen = next_datagram_size_fd(fd);
-        if (buflen == -ENETDOWN)
-                /* the link is down. Don't return an error or the I/O event
-                   source will be disconnected and we won't be able to receive
-                   packets again when the link comes back. */
+        if (buflen < 0) {
+                if (ERRNO_IS_TRANSIENT(buflen) || ERRNO_IS_DISCONNECT(buflen))
+                        return 0;
+
+                log_dhcp_client_errno(client, buflen, "Failed to determine datagram size to read, ignoring: %m");
                 return 0;
-        if (buflen < 0)
-                return buflen;
+        }
 
         message = malloc0(buflen);
         if (!message)
@@ -1944,12 +1944,11 @@ static int client_receive_message_udp(
 
         len = recv(fd, message, buflen, 0);
         if (len < 0) {
-                /* see comment above for why we shouldn't error out on ENETDOWN. */
-                if (ERRNO_IS_TRANSIENT(errno) || errno == ENETDOWN)
+                if (ERRNO_IS_TRANSIENT(errno) || ERRNO_IS_DISCONNECT(errno))
                         return 0;
 
-                return log_dhcp_client_errno(client, errno,
-                                             "Could not receive message from UDP socket: %m");
+                log_dhcp_client_errno(client, errno, "Could not receive message from UDP socket, ignoring: %m");
+                return 0;
         }
         if ((size_t) len < sizeof(DHCPMessage)) {
                 log_dhcp_client(client, "Too small to be a DHCP message: ignoring");
@@ -1995,7 +1994,8 @@ static int client_receive_message_udp(
                 return 0;
         }
 
-        return client_handle_message(client, message, len);
+        (void) client_handle_message(client, message, len);
+        return 0;
 }
 
 static int client_receive_message_raw(
@@ -2023,10 +2023,13 @@ static int client_receive_message_raw(
         assert(client);
 
         buflen = next_datagram_size_fd(fd);
-        if (buflen == -ENETDOWN)
+        if (buflen < 0) {
+                if (ERRNO_IS_TRANSIENT(buflen) || ERRNO_IS_DISCONNECT(buflen))
+                        return 0;
+
+                log_dhcp_client_errno(client, buflen, "Failed to determine datagram size to read, ignoring: %m");
                 return 0;
-        if (buflen < 0)
-                return buflen;
+        }
 
         packet = malloc0(buflen);
         if (!packet)
@@ -2036,10 +2039,11 @@ static int client_receive_message_raw(
 
         len = recvmsg_safe(fd, &msg, 0);
         if (len < 0) {
-                if (ERRNO_IS_TRANSIENT(len) || len == -ENETDOWN)
+                if (ERRNO_IS_TRANSIENT(len) || ERRNO_IS_DISCONNECT(len))
                         return 0;
-                return log_dhcp_client_errno(client, len,
-                                             "Could not receive message from raw socket: %m");
+
+                log_dhcp_client_errno(client, len, "Could not receive message from raw socket, ignoring: %m");
+                return 0;
         }
         if ((size_t) len < sizeof(DHCPPacket))
                 return 0;
@@ -2056,7 +2060,8 @@ static int client_receive_message_raw(
 
         len -= DHCP_IP_UDP_SIZE;
 
-        return client_handle_message(client, &packet->dhcp, len);
+        (void) client_handle_message(client, &packet->dhcp, len);
+        return 0;
 }
 
 int sd_dhcp_client_send_renew(sd_dhcp_client *client) {