diff options
| -rw-r--r-- | THANKS.in | 1 | ||||
| -rw-r--r-- | plugins-root/check_dhcp.c | 38 |
2 files changed, 29 insertions, 10 deletions
@@ -215,3 +215,4 @@ Marlo Bell Stefan Meier Mark Favas Felix Frank +Denis Knauf diff --git a/plugins-root/check_dhcp.c b/plugins-root/check_dhcp.c index 245946b5..993531cd 100644 --- a/plugins-root/check_dhcp.c +++ b/plugins-root/check_dhcp.c @@ -182,6 +182,7 @@ typedef struct requested_server_struct{ #define DHCP_OPTION_BROADCAST_ADDRESS 28 #define DHCP_OPTION_REQUESTED_ADDRESS 50 #define DHCP_OPTION_LEASE_TIME 51 +#define DHCP_OPTION_SERVER_IDENTIFIER 54 #define DHCP_OPTION_RENEWAL_TIME 58 #define DHCP_OPTION_REBINDING_TIME 59 @@ -765,9 +766,9 @@ int add_requested_server(struct in_addr server_address){ int add_dhcp_offer(struct in_addr source,dhcp_packet *offer_packet){ dhcp_offer *new_offer; int x; - int y; unsigned option_type; unsigned option_length; + struct in_addr serv_ident = {0}; if(offer_packet==NULL) return ERROR; @@ -789,23 +790,28 @@ int add_dhcp_offer(struct in_addr source,dhcp_packet *offer_packet){ printf("Option: %d (0x%02X)\n",option_type,option_length); /* get option data */ - if(option_type==DHCP_OPTION_LEASE_TIME){ + switch(option_type){ + case DHCP_OPTION_LEASE_TIME: memcpy(&dhcp_lease_time, &offer_packet->options[x],sizeof(dhcp_lease_time)); dhcp_lease_time = ntohl(dhcp_lease_time); - } - if(option_type==DHCP_OPTION_RENEWAL_TIME){ + break; + case DHCP_OPTION_RENEWAL_TIME: memcpy(&dhcp_renewal_time, &offer_packet->options[x],sizeof(dhcp_renewal_time)); dhcp_renewal_time = ntohl(dhcp_renewal_time); - } - if(option_type==DHCP_OPTION_REBINDING_TIME){ + break; + case DHCP_OPTION_REBINDING_TIME: memcpy(&dhcp_rebinding_time, &offer_packet->options[x],sizeof(dhcp_rebinding_time)); dhcp_rebinding_time = ntohl(dhcp_rebinding_time); + break; + case DHCP_OPTION_SERVER_IDENTIFIER: + memcpy(&serv_ident.s_addr, &offer_packet->options[x],sizeof(serv_ident.s_addr)); + break; } /* skip option data we're ignoring */ - else - for(y=0;y<option_length;y++,x++); - } + if(option_type!=DHCP_OPTION_REBINDING_TIME) + x+=option_length; + } if(verbose){ if(dhcp_lease_time==DHCP_INFINITE_TIME) @@ -826,7 +832,19 @@ int add_dhcp_offer(struct in_addr source,dhcp_packet *offer_packet){ if(new_offer==NULL) return ERROR; - new_offer->server_address=source; + /* + * RFC 2131 (2.) says: "DHCP clarifies the interpretation of the + * 'siaddr' field as the address of the server to use in the next step + * of the client's bootstrap process. A DHCP server may return its own + * address in the 'siaddr' field, if the server is prepared to supply + * the next bootstrap service (e.g., delivery of an operating system + * executable image). A DHCP server always returns its own address in + * the 'server identifier' option." 'serv_ident' is the 'server + * identifier' option, 'source' is the 'siaddr' field or (if 'siaddr' + * wasn't available) the IP address we received the DHCPOFFER from. If + * 'serv_ident' isn't available for some reason, we use 'source'. + */ + new_offer->server_address=serv_ident.s_addr?serv_ident:source; new_offer->offered_address=offer_packet->yiaddr; new_offer->lease_time=dhcp_lease_time; new_offer->renewal_time=dhcp_renewal_time; |