8d3efaf35
Denys Vlasenko
2013-11-03
Subject
udhcpc: allow zero server-id. Closes 6614.
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networking/udhcp/dhcpc.c+25 -11
| @@ -667,6 +667,15 @@ static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet) | |
| client_config.ifindex); | |
| } | |
| + | static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server) |
| + | { |
| + | if (server) |
| + | return udhcp_send_kernel_packet(packet, |
| + | ciaddr, CLIENT_PORT, |
| + | server, SERVER_PORT); |
| + | return raw_bcast_from_client_config_ifindex(packet); |
| + | } |
| + | |
| /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */ | |
| /* NOINLINE: limit stack usage in caller */ | |
| static NOINLINE int send_discover(uint32_t xid, uint32_t requested) | |
| @@ -773,11 +782,7 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr) | |
| add_client_options(&packet); | |
| bb_info_msg("Sending renew..."); | |
| - | if (server) |
| - | return udhcp_send_kernel_packet(&packet, |
| - | ciaddr, CLIENT_PORT, |
| - | server, SERVER_PORT); |
| - | return raw_bcast_from_client_config_ifindex(&packet); |
| + | return bcast_or_ucast(&packet, ciaddr, server); |
| } | |
| #if ENABLE_FEATURE_UDHCPC_ARPING | |
| @@ -826,7 +831,11 @@ static int send_release(uint32_t server, uint32_t ciaddr) | |
| udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server); | |
| bb_info_msg("Sending release..."); | |
| - | return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT); |
| + | /* Note: normally we unicast here since "server" is not zero. |
| + | * However, there _are_ people who run "address-less" DHCP servers, |
| + | * and reportedly ISC dhcp client and Windows allow that. |
| + | */ |
| + | return bcast_or_ucast(&packet, ciaddr, server); |
| } | |
| /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */ | |
| @@ -1648,14 +1657,19 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) | |
| * might work too. | |
| * "Next server" and router are definitely wrong ones to use, though... | |
| */ | |
| + | /* We used to ignore pcakets without DHCP_SERVER_ID. |
| + | * I've got user reports from people who run "address-less" servers. |
| + | * 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; |
| temp = udhcp_get_option(&packet, DHCP_SERVER_ID); | |
| if (!temp) { | |
| - | bb_error_msg("no server ID, ignoring packet"); |
| - | continue; |
| - | /* still selecting - this server looks bad */ |
| + | bb_error_msg("no server ID, using 0.0.0.0"); |
| + | } else { |
| + | /* it IS unaligned sometimes, don't "optimize" */ |
| + | move_from_unaligned32(server_addr, temp); |
| } | |
| - | /* it IS unaligned sometimes, don't "optimize" */ |
| - | move_from_unaligned32(server_addr, temp); |
| /*xid = packet.xid; - already is */ | |
| requested_ip = packet.yiaddr; | |