udhcpc: rename server_addr to server_id, fix id comparison if it's not specified

Even though it is _meant to be_ an IP address, in the wild servers sometimes
give bogus server ids, like 1.1.1.1

function                                             old     new   delta
udhcpc_main                                         2551    2542      -9

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 19 insertions, 25 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 1c3c478ac..d67f60c00 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -1113,7 +1113,7 @@ static void change_listen_mode(int new_mode)
         /* else LISTEN_NONE: client_data.sockfd stays closed */
 }
 
-static void perform_release(uint32_t server_addr, uint32_t requested_ip)
+static void perform_release(uint32_t server_id, uint32_t requested_ip)
 {
         char buffer[sizeof("255.255.255.255")];
         struct in_addr temp_addr;
@@ -1126,13 +1126,13 @@ static void perform_release(uint32_t server_addr, uint32_t requested_ip)
          || client_data.state == REBINDING
          || client_data.state == RENEW_REQUESTED
         ) {
-                temp_addr.s_addr = server_addr;
+                temp_addr.s_addr = server_id;
                 strcpy(buffer, inet_ntoa(temp_addr));
                 temp_addr.s_addr = requested_ip;
                 bb_info_msg("unicasting a release of %s to %s",
                                 inet_ntoa(temp_addr), buffer);
                 client_data.xid = random_xid(); //TODO: can omit?
-                send_release(server_addr, requested_ip); /* unicast */
+                send_release(server_id, requested_ip); /* unicast */
         }
         bb_simple_info_msg("entering released state");
 /*
@@ -1218,7 +1218,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         int tryagain_timeout = 20;
         int discover_timeout = 3;
         int discover_retries = 3;
-        uint32_t server_addr = server_addr; /* for compiler */
+        uint32_t server_id = server_id; /* for compiler */
         uint32_t requested_ip = 0;
         int packet_num;
         int timeout; /* must be signed */
@@ -1481,7 +1481,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                         case REQUESTING:
                                 if (packet_num < 3) {
                                         /* send broadcast select packet */
-                                        send_select(server_addr, requested_ip);
+                                        send_select(server_id, requested_ip);
                                         timeout = discover_timeout;
                                         packet_num++;
                                         continue;
@@ -1512,7 +1512,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                          * Anyway, it does recover by eventually failing through
                          * into INIT_SELECTING state.
                          */
-                                        if (send_renew(server_addr, requested_ip) >= 0) {
+                                        if (send_renew(server_id, requested_ip) >= 0) {
                                                 timeout = discover_timeout;
                                                 packet_num++;
                                                 continue;
@@ -1603,7 +1603,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                         timeout = 0;
                         continue;
                 case SIGUSR2:
-                        perform_release(server_addr, requested_ip);
+                        perform_release(server_id, requested_ip);
                         /* ^^^ switches to LISTEN_NONE */
                         timeout = INT_MAX;
                         continue;
@@ -1688,13 +1688,13 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
  * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
  * They say ISC DHCP client supports this case.
  */
-                                server_addr = 0;
+                                server_id = 0;
                                 temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
                                 if (!temp) {
                                         bb_simple_info_msg("no server ID, using 0.0.0.0");
                                 } else {
                                         /* it IS unaligned sometimes, don't "optimize" */
-                                        move_from_unaligned32(server_addr, temp);
+                                        move_from_unaligned32(server_id, temp);
                                 }
                                 /*xid = packet.xid; - already is */
                                 temp_addr.s_addr = requested_ip = packet.yiaddr;
@@ -1718,7 +1718,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 
                                 change_listen_mode(LISTEN_NONE);
 
-                                temp_addr.s_addr = server_addr;
+                                temp_addr.s_addr = server_id;
                                 strcpy(server_str, inet_ntoa(temp_addr));
                                 temp_addr.s_addr = packet.yiaddr;
 
@@ -1766,7 +1766,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                                 bb_simple_info_msg("offered address is in use "
                                                         "(got ARP reply), declining");
                                                 client_data.xid = random_xid(); //TODO: can omit?
-                                                send_decline(server_addr, packet.yiaddr);
+                                                send_decline(server_id, packet.yiaddr);
 
                                                 if (client_data.state != REQUESTING)
                                                         d4_run_script_deconfig();
@@ -1810,20 +1810,14 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                  * "wrong" server can reply first, with a NAK.
                                  * Do not interpret it as a NAK from "our" server.
                                  */
-                                if (server_addr != 0) {
-                                        uint32_t svid;
-                                        uint8_t *temp;
-
-                                        temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
-                                        if (!temp) {
- non_matching_svid:
-                                                log1("received DHCP NAK with wrong"
-                                                        " server ID%s", ", ignoring packet");
-                                                continue;
-                                        }
+                                uint32_t svid = 0; /* we treat no server id as 0.0.0.0 */
+                                uint8_t *temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
+                                if (temp)
                                         move_from_unaligned32(svid, temp);
-                                        if (svid != server_addr)
-                                                goto non_matching_svid;
+                                if (svid != server_id) {
+                                        log1("received DHCP NAK with wrong"
+                                                " server ID%s", ", ignoring packet");
+                                        continue;
                                 }
                                 /* return to init state */
                                 change_listen_mode(LISTEN_NONE);
@@ -1847,7 +1841,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 
  ret0:
         if (opt & OPT_R) /* release on quit */
-                perform_release(server_addr, requested_ip);
+                perform_release(server_id, requested_ip);
         retval = 0;
  ret:
         /*if (client_data.pidfile) - remove_pidfile has its own check */