diff options
Diffstat (limited to 'server/dhcp.c')
| -rw-r--r-- | server/dhcp.c | 107 |
1 files changed, 55 insertions, 52 deletions
diff --git a/server/dhcp.c b/server/dhcp.c index 35648561..21fadf57 100644 --- a/server/dhcp.c +++ b/server/dhcp.c @@ -34,7 +34,7 @@ #ifndef lint static char copyright[] = -"$Id: dhcp.c,v 1.192.2.66 2007/03/27 03:49:20 dhankins Exp $ Copyright (c) 2004-2007 Internet Systems Consortium. All rights reserved.\n"; +"$Id: dhcp.c,v 1.192.2.67 2007/04/20 15:27:36 dhankins Exp $ Copyright (c) 2004-2007 Internet Systems Consortium. All rights reserved.\n"; #endif /* not lint */ #include "dhcpd.h" @@ -98,38 +98,31 @@ void dhcp (packet) } /* There is a problem with the relay agent information option, - which is that in order for a normal relay agent to append - this option, the relay agent has to have been involved in - getting the packet from the client to the server. Note - that this is the software entity known as the relay agent, - _not_ the hardware entity known as a router in which the - relay agent may be running, so the fact that a router has - forwarded a packet does not mean that the relay agent in - the router was involved. - - So when the client is in INIT or INIT-REBOOT or REBINDING - state, the relay agent gets to tack on its options, but - when it's not, the relay agent doesn't get to do this, - which means that any decisions the DHCP server may make - based on the agent options will be made incorrectly. - - We work around this in the following way: if this is a - DHCPREQUEST and doesn't have relay agent information - options, we see if there's an existing lease for this IP - address and this client that _does_ have stashed agent - options. If so, then we tack those options onto the - packet as if they came from the client. Later on, when we - are deciding whether to steal the agent options from the - packet, if the agent options stashed on the lease are the - same as those stashed on the packet, we don't steal them - - this ensures that the client never receives its agent - options. */ - - if (packet -> packet_type == DHCPREQUEST && - packet -> raw -> ciaddr.s_addr && - !packet -> raw -> giaddr.s_addr && - (packet -> options -> universe_count < agent_universe.index || - !packet -> options -> universes [agent_universe.index])) + * which is that in order for a normal relay agent to append + * this option, the relay agent has to have been involved in + * getting the packet from the client to the server. Note + * that this is the software entity known as the relay agent, + * _not_ the hardware entity known as a router in which the + * relay agent may be running, so the fact that a router has + * forwarded a packet does not mean that the relay agent in + * the router was involved. + * + * So when the client broadcasts (DHCPDISCOVER, or giaddr is set), + * we can be sure that there are either agent options in the + * packet, or there aren't supposed to be. When the giaddr is not + * set, it's still possible that the client is on a directly + * attached subnet, and agent options are being appended by an l2 + * device that has no address, and so sets no giaddr. + * + * But in either case it's possible that the packets we receive + * from the client in RENEW state may not include the agent options, + * so if they are not in the packet we must "pretend" the last values + * we observed were provided. + */ + if (packet->packet_type == DHCPREQUEST && + packet->raw->ciaddr.s_addr && !packet->raw->giaddr.s_addr && + (packet->options->universe_count <= agent_universe.index || + packet->options->universes[agent_universe.index] == NULL)) { struct iaddr cip; @@ -185,6 +178,12 @@ void dhcp (packet) &(packet -> options -> universes [agent_universe.index]), lease -> agent_options, MDL); + + if (packet->options->universe_count <= agent_universe.index) + packet->options->universe_count = + agent_universe.index + 1; + + packet->agent_options_stashed = ISC_TRUE; } nolease: @@ -1555,20 +1554,28 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp, hp) * on the lease. We do not check giaddr to detect the presence of * a relay, as this excludes "l2" relay agents which have no giaddr * to set. + * + * XXX: If the user configures options for the relay agent information + * (state->options->universes[agent_universe.index] is not NULL), + * we're still required to duplicate other values provided by the + * relay agent. So we need to merge the old values not configured + * by the user into the new state, not just give up. */ - if (packet->options->universe_count > agent_universe.index && - packet->options->universes [agent_universe.index] && - (state -> options -> universe_count <= agent_universe.index || - !state -> options -> universes [agent_universe.index]) && - lease -> agent_options != - ((struct option_chain_head *) - packet -> options -> universes [agent_universe.index])) { + if (!packet->agent_options_stashed && + packet->options->universe_count > agent_universe.index && + packet->options->universes[agent_universe.index] != NULL && + (state->options->universe_count <= agent_universe.index || + state->options->universes[agent_universe.index] == NULL)) { option_chain_head_reference ((struct option_chain_head **) &(state -> options -> universes [agent_universe.index]), (struct option_chain_head *) packet -> options -> universes [agent_universe.index], MDL); + + if (state->options->universe_count <= agent_universe.index) + state->options->universe_count = + agent_universe.index + 1; } /* If we are offering a lease that is still currently valid, preserve @@ -2204,19 +2211,15 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp, hp) option_chain_head_reference (< -> agent_options, lease -> agent_options, MDL); - /* If we got relay agent information options, and the packet really - * looks like it came through a relay agent, and if this feature is - * not disabled, save the relay agent information options that came - * in with the packet, so that we can use them at renewal time when - * the packet won't have gone through a relay agent. We do not - * check giaddr to detect the presence of a relay, as this excludes - * "l2" relay agents which have no giaddr to set. + /* If we got relay agent information options from the packet, then + * cache them for renewal in case the relay agent can't supply them + * when the client unicasts. The options may be from an addressed + * "l3" relay, or from an unaddressed "l2" relay which does not set + * giaddr. */ - if (packet->options->universe_count > agent_universe.index && - packet->options->universes [agent_universe.index] && - (state -> options -> universe_count <= agent_universe.index || - state -> options -> universes [agent_universe.index] == - packet -> options -> universes [agent_universe.index])) { + if (!packet->agent_options_stashed && + packet->options->universe_count > agent_universe.index && + packet->options->universes[agent_universe.index] != NULL) { oc = lookup_option (&server_universe, state -> options, SV_STASH_AGENT_OPTIONS); if (!oc || |