src/dnsmasq.h

   1 /* dnsmasq is Copyright (c) 2000-2003 Simon Kelley
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 dated June, 1991.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11 */
  12
  13 /* Author's email: simon@thekelleys.org.uk */
  14
  15 /* for pselect.... */
  16 #define _XOPEN_SOURCE 600
  17 /* but then DNS headers don't compile without.... */
  18 #define _BSD_SOURCE
  19 /* and also, on FreeBSD 5.0 ..... */
  20 #define __BSD_VISIBLE 1
  21
  22 /* get these before config.h  for IPv6 stuff... */
  23 #include <sys/types.h>
  24 #include <netinet/in.h>
  25
  26 /* get this before config.h too. */
  27 #include <syslog.h>
  28
  29 #include "config.h"
  30
  31 #include <arpa/nameser.h>
  32 #include <arpa/inet.h>
  33 #include <sys/stat.h>
  34 #include <sys/socket.h>
  35 #include <sys/stat.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/select.h>
  38 #if defined(__sun) || defined(__sun__)
  39 #include <sys/sockio.h>
  40 #endif
  41 #include <sys/time.h>
  42 #include <net/if.h>
  43 #include <unistd.h>
  44 #include <stdio.h>
  45 #include <string.h>
  46 #include <stdlib.h>
  47 #include <fcntl.h>
  48 #include <ctype.h>
  49 #include <signal.h>
  50 #ifdef HAVE_GETOPT_LONG
  51 #  include <getopt.h>
  52 #endif
  53 #include <time.h>
  54 #include <errno.h>
  55 #include <pwd.h>
  56 #include <grp.h>
  57 #include <net/ethernet.h>
  58 #include <net/if_arp.h>
  59 #include <netinet/in_systm.h>
  60 #include <netinet/ip.h>
  61 #ifdef HAVE_PF_PACKET
  62 #include <netpacket/packet.h>
  63 #endif
  64 #ifdef HAVE_BPF
  65 #include <net/bpf.h>
  66 #include <net/if_dl.h>
  67 #endif
  68 #include <sys/uio.h>
  69
  70 #define OPT_BOGUSPRIV      1
  71 #define OPT_FILTER         2
  72 #define OPT_LOG            4
  73 #define OPT_SELFMX         8
  74 #define OPT_NO_HOSTS       16
  75 #define OPT_NO_POLL        32
  76 #define OPT_DEBUG          64
  77 #define OPT_ORDER          128
  78 #define OPT_NO_RESOLV      256
  79 #define OPT_EXPAND         512
  80 #define OPT_LOCALMX        1024
  81 #define OPT_NO_NEG         2048
  82 #define OPT_NODOTS_LOCAL   4096
  83
  84 struct all_addr {
  85   union {
  86     struct in_addr addr4;
  87 #ifdef HAVE_IPV6
  88     struct in6_addr addr6;
  89 #endif
  90   } addr;
  91 };
  92
  93 struct bogus_addr {
  94   struct in_addr addr;
  95   struct bogus_addr *next;
  96 };
  97
  98 union bigname {
  99   char name[MAXDNAME];
 100   union bigname *next; /* freelist */
 101 };
 102
 103 struct crec {
 104   struct crec *next, *prev, *hash_next;
 105   time_t ttd; /* time to die */
 106   struct all_addr addr;
 107   unsigned short flags;
 108   union {
 109     char sname[SMALLDNAME];
 110     union bigname *bname;
 111     char *namep;
 112   } name;
 113 };
 114
 115 #define F_IMMORTAL  1
 116 #define F_CONFIG    2
 117 #define F_REVERSE   4
 118 #define F_FORWARD   8
 119 #define F_DHCP      16
 120 #define F_NEG       32
 121 #define F_HOSTS     64
 122 #define F_IPV4      128
 123 #define F_IPV6      256
 124 #define F_BIGNAME   512
 125 #define F_UPSTREAM  1024
 126 #define F_SERVER    2048
 127 #define F_NXDOMAIN  4096
 128 #define F_QUERY     8192
 129 #define F_ADDN      16384
 130 #define F_NOERR     32768
 131
 132 /* struct sockaddr is not large enough to hold any address,
 133    and specifically not big enough to hold and IPv6 address.
 134    Blech. Roll our own. */
 135 union mysockaddr {
 136   struct sockaddr sa;
 137   struct sockaddr_in in;
 138 #ifdef HAVE_BROKEN_SOCKADDR_IN6
 139   /* early versions of glibc don't include sin6_scope_id in sockaddr_in6
 140      but latest kernels _require_ it to be set. The choice is to have
 141      dnsmasq fail to compile on back-level libc or fail to run
 142      on latest kernels with IPv6. Or to do this: sorry that it's so gross. */
 143   struct my_sockaddr_in6 {
 144     sa_family_t     sin6_family;    /* AF_INET6 */
 145     uint16_t        sin6_port;      /* transport layer port # */
 146     uint32_t        sin6_flowinfo;  /* IPv6 traffic class & flow info */
 147     struct in6_addr sin6_addr;      /* IPv6 address */
 148     uint32_t        sin6_scope_id;  /* set of interfaces for a scope */
 149   } in6;
 150 #elif defined(HAVE_IPV6)
 151   struct sockaddr_in6 in6;
 152 #endif
 153 };
 154
 155 #define SERV_FROM_RESOLV     1  /* 1 for servers from resolv, 0 for command line. */
 156 #define SERV_NO_ADDR         2  /* no server, this domain is local only */
 157 #define SERV_LITERAL_ADDRESS 4  /* addr is the answer, not the server */
 158 #define SERV_HAS_SOURCE      8  /* source address specified */
 159 #define SERV_HAS_DOMAIN     16  /* server for one domain only */
 160 #define SERV_FOR_NODOTS     32  /* server for names with no domain part only */
 161 #define SERV_TYPE    (SERV_HAS_DOMAIN | SERV_FOR_NODOTS)
 162
 163 struct serverfd {
 164   int fd;
 165   union mysockaddr source_addr;
 166   struct serverfd *next;
 167 };
 168
 169 struct server {
 170   union mysockaddr addr, source_addr;
 171   struct serverfd *sfd; /* non-NULL if this server has its own fd bound to
 172                            a source port */
 173   char *domain; /* set if this server only handles a domain. */
 174   int flags;
 175   struct server *next;
 176 };
 177
 178 /* linked list of all the interfaces in the system and
 179    the sockets we have bound to each one. */
 180 struct irec {
 181   union mysockaddr addr;
 182   int fd;
 183   int valid;
 184   struct irec *next;
 185 };
 186
 187 /* interface and address parms from command line. */
 188 struct iname {
 189   char *name;
 190   union mysockaddr addr;
 191   int found;
 192   struct iname *next;
 193 };
 194
 195 /* resolv-file parms from command-line */
 196 struct resolvc {
 197   struct resolvc *next;
 198   int is_default;
 199   int logged;
 200   char *name;
 201 };
 202
 203 struct frec {
 204   union mysockaddr source;
 205   struct server *sentto;
 206   unsigned short orig_id, new_id;
 207   int fd;
 208   time_t time;
 209   struct frec *next;
 210 };
 211
 212 struct dhcp_lease {
 213   int clid_len;          /* length of client identifier */
 214   unsigned char *clid;   /* clientid */
 215   char *hostname, *fqdn; /* name from client-hostname option or config */
 216   time_t expires;        /* lease expiry */
 217   unsigned char hwaddr[ETHER_ADDR_LEN];
 218   struct in_addr addr;
 219   struct dhcp_lease *next;
 220 };
 221
 222 struct dhcp_config {
 223   int clid_len;          /* length of client identifier */
 224   unsigned char *clid;   /* clientid */
 225   unsigned char hwaddr[ETHER_ADDR_LEN];
 226   char *hostname;
 227   struct in_addr addr;
 228   unsigned int lease_time;
 229   struct dhcp_config *next;
 230 };
 231
 232 struct dhcp_opt {
 233   int opt, len, is_addr;
 234   unsigned char *val;
 235   struct dhcp_opt *next;
 236  };
 237
 238 struct dhcp_context {
 239   int fd, rawfd, ifindex;
 240   char *iface;
 241   unsigned char hwaddr[ETHER_ADDR_LEN];
 242   unsigned int lease_time;
 243   struct in_addr serv_addr, netmask, broadcast;
 244   struct in_addr start, end, last; /* range of available addresses */
 245   struct dhcp_context *next;
 246 };
 247
 248 typedef unsigned char u8;
 249 typedef unsigned short u16;
 250 typedef unsigned int u32;
 251
 252
 253 struct udp_dhcp_packet {
 254         struct ip ip;
 255         struct udphdr {
 256           u16 uh_sport;               /* source port */
 257           u16 uh_dport;               /* destination port */
 258           u16 uh_ulen;                /* udp length */
 259           u16 uh_sum;                 /* udp checksum */
 260         } udp;
 261         struct dhcp_packet {
 262           u8 op, htype, hlen, hops;
 263           u32 xid;
 264           u16 secs, flags;
 265           struct in_addr ciaddr, yiaddr, siaddr, giaddr;
 266           u8 chaddr[16], sname[64], file[128];
 267           u32 cookie;
 268           u8 options[308];
 269         } data;
 270 };
 271
 272
 273 /* cache.c */
 274 void cache_init(int cachesize, int log);
 275 void log_query(unsigned short flags, char *name, struct all_addr *addr);
 276 struct crec *cache_find_by_addr(struct crec *crecp,
 277                                 struct all_addr *addr, time_t now,
 278                                 unsigned short prot);
 279 struct crec *cache_find_by_name(struct crec *crecp,
 280                                 char *name, time_t now, unsigned short  prot);
 281 void cache_end_insert(void);
 282 void cache_start_insert(void);
 283 void cache_insert(char *name, struct all_addr *addr,
 284                   time_t now, unsigned long ttl, unsigned short flags);
 285 void cache_reload(int opts, char *buff, char *domain_suffix, char *addn_hosts);
 286 void cache_add_dhcp_entry(char *host_name, struct in_addr *host_address,
 287                           time_t ttd, unsigned short flags);
 288 void cache_unhash_dhcp(void);
 289 void dump_cache(int debug, int size);
 290 char *cache_get_name(struct crec *crecp);
 291
 292 /* rfc1035.c */
 293 unsigned short extract_request(HEADER *header, unsigned int qlen, char *name);
 294 int setup_reply(HEADER *header, unsigned int qlen,
 295                 struct all_addr *addrp, unsigned short flags,
 296                 unsigned long local_ttl);
 297 void extract_addresses(HEADER *header, unsigned int qlen, char *namebuff, time_t now);
 298 void extract_neg_addrs(HEADER *header, unsigned int qlen, char *namebuff, time_t now);
 299 int answer_request(HEADER *header, char *limit, unsigned int qlen, char *mxname,
 300                    char *mxtarget, unsigned int options, time_t now, unsigned long local_ttl,
 301                    char *namebuff);
 302 int check_for_bogus_wildcard(HEADER *header, unsigned int qlen, char *name,
 303                              struct bogus_addr *addr, time_t now);
 304
 305 /* util.c */
 306 unsigned short rand16(void);
 307 int legal_char(char c);
 308 int canonicalise(char *s);
 309 void die(char *message, char *arg1);
 310 void complain(char *message, char *arg1);
 311 void *safe_malloc(int size);
 312 char *safe_string_alloc(char *cp);
 313 int sa_len(union mysockaddr *addr);
 314 int sockaddr_isequal(union mysockaddr *s1, union mysockaddr *s2);
 315 int hostname_isequal(unsigned char *a, unsigned char *b);
 316
 317 /* option.c */
 318 unsigned int read_opts(int argc, char **argv, char *buff, struct resolvc **resolv_file,
 319                        char **mxname, char **mxtarget, char **lease_file,
 320                        char **username, char **groupname,
 321                        char **domain_suffix, char **runfile,
 322                        struct iname **if_names, struct iname **if_addrs, struct iname **if_except,
 323                        struct bogus_addr **bogus_addr, struct server **serv_addrs, int *cachesize,
 324                        int *port, int *query_port, unsigned long *local_ttl, char **addn_hosts,
 325                        struct dhcp_context **dhcp, struct dhcp_config **dhcp_conf, struct dhcp_opt **opts,
 326                        char **dhcp_file, char **dhcp_sname, struct in_addr *dhcp_next_server);
 327
 328 /* forward.c */
 329 void forward_init(int first);
 330 void reap_forward(int fd);
 331 struct server *forward_query(int udpfd, union mysockaddr *udpaddr, HEADER *header,
 332                              int plen, unsigned int options, char *dnamebuff,
 333                              struct server *servers, struct server *last_server,
 334                              time_t now, unsigned long local_ttl);
 335 struct server *reply_query(int fd, int options, char *packet, time_t now,
 336                            char *dnamebuff, struct server *last_server,
 337                            struct bogus_addr *bogus_nxdomain);
 338
 339 /* network.c */
 340 struct server *reload_servers(char *fname, char *buff, struct server *servers, int query_port);
 341 struct server *check_servers(struct server *new, struct irec *interfaces, struct serverfd **sfds);
 342 char *enumerate_interfaces(struct irec **interfaces,
 343                            struct iname *names,
 344                            struct iname *addrs,
 345                            struct iname *except,
 346                            struct dhcp_context *dhcp,
 347                            int port);
 348
 349 /* dhcp.c */
 350 void dhcp_packet(struct dhcp_context *context, char *packet,
 351                  struct dhcp_opt *dhcp_opts,
 352                  struct dhcp_config *dhcp_configs,
 353                  time_t now, char *namebuff, char *domain_suffix,
 354                  char *dhcp_file, char *dhcp_sname, struct in_addr dhcp_next_server);
 355 int address_available(struct dhcp_context *context, struct in_addr addr);
 356 int address_allocate(struct dhcp_context *context, struct dhcp_config *configs,
 357                      struct in_addr *addrp);
 358 struct dhcp_config *find_config(struct dhcp_config *configs,
 359                                 struct dhcp_context *context,
 360                                 unsigned char *clid, int clid_len,
 361                                 unsigned char *hwaddr, char *hostname);
 362
 363 void set_configs_from_cache(struct dhcp_config *configs);
 364 /* lease.c */
 365 void lease_update_dns(int force_dns);
 366 int lease_init(char *lease_file, char *domain, char *buff,
 367                char *buff2, time_t now, struct dhcp_config *dhcp_configs);
 368 struct dhcp_lease *lease_allocate(unsigned char *clid, int clid_len, struct in_addr addr);
 369 void lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr);
 370 void lease_set_hostname(struct dhcp_lease *lease, char *name, char *suffix);
 371 void lease_set_expires(struct dhcp_lease *lease, time_t exp);
 372 struct dhcp_lease *lease_find_by_client(unsigned char *clid, int clid_len);
 373 struct dhcp_lease *lease_find_by_addr(struct in_addr addr);
 374 void lease_prune(struct dhcp_lease *target, time_t now);
 375
 376 /* rfc2131.c */
 377 int dhcp_reply(struct dhcp_context *context, struct dhcp_packet *mess,
 378                unsigned int sz, time_t now, char *namebuff,
 379                struct dhcp_opt *dhcp_opts, struct dhcp_config *dhcp_configs,
 380                char *domain_suffix, char *dhcp_file, char *dhcp_sname,
 381                struct in_addr dhcp_next_server);