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author | Denys Vlasenko | 2013-11-03 19:20:54 +0100 |
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committer | Denys Vlasenko | 2013-11-03 19:20:54 +0100 |
commit | 8d3efaf35eb9d138114563bba4173c39c1231198 (patch) | |
tree | 69b514394ecf1b1f63afbda195359d596c34e7f5 /networking/udhcp/dhcpc.c | |
parent | b21bc80c7651bfb5a9e001cc220a598cf89b7cfd (diff) | |
download | busybox-8d3efaf35eb9d138114563bba4173c39c1231198.zip busybox-8d3efaf35eb9d138114563bba4173c39c1231198.tar.gz |
udhcpc: allow zero server-id. Closes 6614.
function old new delta
bcast_or_ucast - 47 +47
udhcp_send_kernel_packet 271 295 +24
udhcpc_main 2696 2705 +9
udhcp_send_raw_packet 456 459 +3
send_release 90 76 -14
send_renew 105 77 -28
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/2 up/down: 83/-42) Total: 41 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'networking/udhcp/dhcpc.c')
-rw-r--r-- | networking/udhcp/dhcpc.c | 36 |
1 files changed, 25 insertions, 11 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index 53d8a5e..8dee916 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -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; |