1 files changed, 37 insertions, 12 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 99d91bf70..55f21c187 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -1,7 +1,6 @@
 /* vi: set sw=4 ts=4: */
 /*
  * udhcp client
- *
  * Russ Dill <Russ.Dill@asu.edu> July 2001
  *
  * This program is free software; you can redistribute it and/or modify
@@ -694,10 +693,16 @@ static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint
 
 static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
 {
-        if (server)
+        if (server) {
+                /* Without MSG_DONTROUTE, the packet was seen routed over
+                 * _other interface_ if server ID is bogus (example: 1.1.1.1).
+                 */
                 return udhcp_send_kernel_packet(packet,
                         ciaddr, CLIENT_PORT,
-                        server, SERVER_PORT);
+                        server, SERVER_PORT,
+                        /*send_flags: "to hosts only on directly connected networks" */ MSG_DONTROUTE
+                );
+        }
         return raw_bcast_from_client_config_ifindex(packet, ciaddr);
 }
 
@@ -735,7 +740,7 @@ static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
 static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
 {
         struct dhcp_packet packet;
-        struct in_addr addr;
+        struct in_addr temp_addr;
 
 /*
  * RFC 2131 4.3.2 DHCPREQUEST message
@@ -766,8 +771,8 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
          */
         add_client_options(&packet);
 
-        addr.s_addr = requested;
-        bb_error_msg("sending select for %s", inet_ntoa(addr));
+        temp_addr.s_addr = requested;
+        bb_error_msg("sending select for %s", inet_ntoa(temp_addr));
         return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
 }
 
@@ -776,6 +781,7 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
 static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
 {
         struct dhcp_packet packet;
+        struct in_addr temp_addr;
 
 /*
  * RFC 2131 4.3.2 DHCPREQUEST message
@@ -806,7 +812,8 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
          */
         add_client_options(&packet);
 
-        bb_error_msg("sending %s", "renew");
+        temp_addr.s_addr = server;
+        bb_error_msg("sending renew to %s", inet_ntoa(temp_addr));
         return bcast_or_ucast(&packet, ciaddr, server);
 }
 
@@ -1010,9 +1017,14 @@ static int udhcp_raw_socket(int ifindex)
          */
         log2("got raw socket fd");
 
+        memset(&sock, 0, sizeof(sock)); /* let's be deterministic */
         sock.sll_family = AF_PACKET;
         sock.sll_protocol = htons(ETH_P_IP);
         sock.sll_ifindex = ifindex;
+        /*sock.sll_hatype = ARPHRD_???;*/
+        /*sock.sll_pkttype = PACKET_???;*/
+        /*sock.sll_halen = ???;*/
+        /*sock.sll_addr[8] = ???;*/
         xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
 
 #if 0 /* Several users reported breakage when BPF filter is used */
@@ -1519,11 +1531,24 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                          * Anyway, it does recover by eventually failing through
                          * into INIT_SELECTING state.
                          */
-                                        send_renew(xid, server_addr, requested_ip);
-                                        timeout >>= 1;
-                                        continue;
+                                        if (send_renew(xid, server_addr, requested_ip) >= 0) {
+                                                timeout >>= 1;
+//TODO: the timeout to receive an answer for our renew should not be selected
+//with "timeout = lease_seconds / 2; ...; timeout = timeout / 2": it is often huge.
+//Waiting e.g. 4*3600 seconds for a reply does not make sense
+//(if reply isn't coming, we keep an open socket for hours),
+//it should be something like 10 seconds.
+//Also, it's probably best to try sending renew in kernel mode a few (3-5) times
+//and fall back to raw mode if it does not work.
+                                                continue;
+                                        }
+                                        /* else: error sending.
+                                         * example: ENETUNREACH seen with server
+                                         * which gave us bogus server ID 1.1.1.1
+                                         * which wasn't reachable (and probably did not exist).
+                                         */
                                 }
-                                /* Timed out, enter rebinding state */
+                                /* Timed out or error, enter rebinding state */
                                 log1("entering rebinding state");
                                 state = REBINDING;
                                 /* fall right through */
@@ -1605,7 +1630,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                 len = udhcp_recv_raw_packet(&packet, sockfd);
                         if (len == -1) {
                                 /* Error is severe, reopen socket */
-                                bb_error_msg("read error: %s, reopening socket", strerror(errno));
+                                bb_error_msg("read error: "STRERROR_FMT", reopening socket" STRERROR_ERRNO);
                                 sleep(discover_timeout); /* 3 seconds by default */
                                 change_listen_mode(listen_mode); /* just close and reopen */
                         }