udhcpc: remove code which requires server ID to be on local network

This reverts "udhcpc: paranoia when using kernel UDP mode
for sending renew: server ID may be bogus".

Users complain that they do have servers behind routers
(with DHCP relays).

function                                             old     new   delta
send_packet                                          168     166      -2
bcast_or_ucast                                        25      23      -2
udhcp_send_kernel_packet                             301     295      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-10)             Total: -10 bytes

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

5 files changed, 8 insertions, 21 deletions

diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index 5f890459c..50ea9199b 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -317,9 +317,7 @@ int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 
 int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
                 uint32_t source_nip, int source_port,
-                uint32_t dest_nip, int dest_port,
-                int send_flags
-) FAST_FUNC;
+                uint32_t dest_nip, int dest_port) FAST_FUNC;
 
 void udhcp_sp_setup(void) FAST_FUNC;
 void udhcp_sp_fd_set(struct pollfd *pfds, int extra_fd) FAST_FUNC;
diff --git a/networking/udhcp/d6_dhcpc.c b/networking/udhcp/d6_dhcpc.c
index 4dbc2b1bd..ed2255ef3 100644
--- a/networking/udhcp/d6_dhcpc.c
+++ b/networking/udhcp/d6_dhcpc.c
@@ -803,15 +803,13 @@ static NOINLINE int send_d6_renew(uint32_t xid, struct in6_addr *server_ipv6, st
         opt_ptr = add_d6_client_options(opt_ptr);
 
         bb_error_msg("sending %s", "renew");
-        if (server_ipv6) {
+        if (server_ipv6)
                 return d6_send_kernel_packet(
                         &packet, (opt_ptr - (uint8_t*) &packet),
                         our_cur_ipv6, CLIENT_PORT6,
                         server_ipv6, SERVER_PORT6,
                         client_config.ifindex
-                        /* TODO? send_flags: MSG_DONTROUTE (see IPv4 code for reason why) */
                 );
-        }
         return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
 }
 
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index c206a5825..c2805a009 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -693,16 +693,10 @@ 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) {
-                /* Without MSG_DONTROUTE, the packet was seen routed over
-                 * _other interface_ if server ID is bogus (example: 1.1.1.1).
-                 */
+        if (server)
                 return udhcp_send_kernel_packet(packet,
                         ciaddr, CLIENT_PORT,
-                        server, SERVER_PORT,
-                        /*send_flags: "to hosts only on directly connected networks" */ MSG_DONTROUTE
-                );
-        }
+                        server, SERVER_PORT);
         return raw_bcast_from_client_config_ifindex(packet, ciaddr);
 }
 
diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index ef59dca5c..a8cd3f03b 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -591,9 +591,7 @@ static void send_packet_to_relay(struct dhcp_packet *dhcp_pkt)
 
         udhcp_send_kernel_packet(dhcp_pkt,
                         server_config.server_nip, SERVER_PORT,
-                        dhcp_pkt->gateway_nip, SERVER_PORT,
-                        /*send_flags:*/ 0
-        );
+                        dhcp_pkt->gateway_nip, SERVER_PORT);
 }
 
 static void send_packet(struct dhcp_packet *dhcp_pkt, int force_broadcast)
diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c
index fc2bb5416..ff16904f7 100644
--- a/networking/udhcp/packet.c
+++ b/networking/udhcp/packet.c
@@ -189,8 +189,7 @@ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 /* Let the kernel do all the work for packet generation */
 int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
                 uint32_t source_nip, int source_port,
-                uint32_t dest_nip, int dest_port,
-                int send_flags)
+                uint32_t dest_nip, int dest_port)
 {
         struct sockaddr_in sa;
         unsigned padding;
@@ -227,8 +226,8 @@ int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
         padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
         if (padding > DHCP_SIZE - 300)
                 padding = DHCP_SIZE - 300;
-        result = send(fd, dhcp_pkt, DHCP_SIZE - padding, send_flags);
-        msg = "send";
+        result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
+        msg = "write";
  ret_close:
         close(fd);
         if (result < 0) {