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Diffstat (limited to 'resolv.c')
| -rw-r--r-- | resolv.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/resolv.c b/resolv.c new file mode 100644 index 0000000000..bcc9211a68 --- /dev/null +++ b/resolv.c @@ -0,0 +1,269 @@ +/* resolv.c + * Routines for network object lookup + * + * Laurent Deniel <deniel@worldnet.fr> + * + * Ethereal - Network traffic analyzer + * By Gerald Combs <gerald@zing.org> + * Copyright 1998 Gerald Combs + * + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * + * To do: + * + * - Add ethernet address resolution + * - In a future live capture and decode mode, + * add hostname entries in hash table from DNS packet decoding. + * + */ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#ifndef AVOID_DNS_TIMEOUT +#define AVOID_DNS_TIMEOUT +#endif + +#include <gtk/gtk.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +#ifdef HAVE_SYS_TYPES_H +# include <sys/types.h> +#endif + +#ifdef HAVE_NETINET_IN_H +# include <netinet/in.h> +#endif + +#include <netdb.h> +#include <signal.h> +#include <sys/socket.h> + +#ifdef AVOID_DNS_TIMEOUT +# include <setjmp.h> +#endif + +#include "packet.h" +#include "resolv.h" + +#define MAXNAMELEN 64 /* max name length (hostname and port name) */ +#define HASHHOSTSIZE 1024 +#define HASHPORTSIZE 256 + +/* hash table used for host and port lookup */ + +typedef struct hashname { + u_int addr; + u_char name[MAXNAMELEN]; + struct hashname *next; +} hashname_t; + +static hashname_t *host_table[HASHHOSTSIZE]; +static hashname_t *udp_port_table[HASHPORTSIZE]; +static hashname_t *tcp_port_table[HASHPORTSIZE]; + +/* global variable that indicates if name resolving is actif */ + +int g_resolving_actif = 1; /* routines are active by default */ + +/* local function definitions */ + +static u_char *serv_name_lookup(u_int port, u_int proto) +{ + + hashname_t *tp; + hashname_t **table; + char *serv_proto = NULL; + struct servent *servp; + int i; + + switch(proto) { + case IPPROTO_UDP: + table = udp_port_table; + serv_proto = "udp"; + break; + case IPPROTO_TCP: + table = tcp_port_table; + serv_proto = "tcp"; + break; + default: + /* not yet implemented */ + return NULL; + /*NOTREACHED*/ + break; + } /* proto */ + + i = port & (HASHPORTSIZE - 1); + tp = table[ i & (HASHPORTSIZE - 1)]; + + if( tp == NULL ) { + tp = table[ i & (HASHPORTSIZE - 1)] = + (hashname_t *)g_malloc(sizeof(hashname_t)); + } else { + while(1) { + if( tp->addr == port ) { + return tp->name; + } + if (tp->next == NULL) { + tp->next = (hashname_t *)g_malloc(sizeof(hashname_t)); + tp = tp->next; + break; + } + tp = tp->next; + } + } + + /* fill in a new entry */ + tp->addr = port; + tp->next = NULL; + + if ((servp = getservbyport(htons(port), serv_proto)) == NULL) { + /* unknown port */ + sprintf(tp->name, "%d", port); + } else { + strncpy(tp->name, servp->s_name, MAXNAMELEN); + } + + return (tp->name); + +} /* serv_name_lookup */ + +#ifdef AVOID_DNS_TIMEOUT + +#define DNS_TIMEOUT 5 /* max sec per call */ + +jmp_buf hostname_env; + +static void abort_network_query(int sig) +{ + longjmp(hostname_env, 1); +} +#endif /* AVOID_DNS_TIMEOUT */ + +static u_char *host_name_lookup(u_int addr) +{ + + hashname_t *tp; + hashname_t **table = host_table; + struct hostent *hostp; + + tp = table[ addr & (HASHHOSTSIZE - 1)]; + + if( tp == NULL ) { + tp = table[ addr & (HASHHOSTSIZE - 1)] = + (hashname_t *)g_malloc(sizeof(hashname_t)); + } else { + while(1) { + if( tp->addr == addr ) { + return tp->name; + } + if (tp->next == NULL) { + tp->next = (hashname_t *)g_malloc(sizeof(hashname_t)); + tp = tp->next; + break; + } + tp = tp->next; + } + } + + /* fill in a new entry */ + tp->addr = addr; + tp->next = NULL; + +#ifdef AVOID_DNS_TIMEOUT + + /* Quick hack to avoid DNS/YP timeout */ + + if (!setjmp(hostname_env)) { + signal(SIGALRM, abort_network_query); + alarm(DNS_TIMEOUT); +#endif + hostp = gethostbyaddr((char *)&addr, 4, AF_INET); +#ifdef AVOID_DNS_TIMEOUT + alarm(0); +#endif + if (hostp != NULL) { + strncpy(tp->name, hostp->h_name, MAXNAMELEN); + return tp->name; + } +#ifdef AVOID_DNS_TIMEOUT + } +#endif + + /* unknown host or DNS timeout */ + + sprintf(tp->name, "%s", ip_to_str((guint8 *)&addr)); + return (tp->name); + +} /* host_name_lookup */ + +/* external functions */ + +extern u_char *get_hostname(u_int addr) +{ + if (!g_resolving_actif) + return ip_to_str((guint8 *)&addr); + + return host_name_lookup(addr); +} + +extern u_char *get_udp_port(u_int port) +{ + static gchar str[3][MAXNAMELEN]; + static gchar *cur; + + if (!g_resolving_actif) { + if (cur == &str[0][0]) { + cur = &str[1][0]; + } else if (cur == &str[1][0]) { + cur = &str[2][0]; + } else { + cur = &str[0][0]; + } + sprintf(cur, "%d", port); + return cur; + } + + return serv_name_lookup(port, IPPROTO_UDP); + +} /* get_udp_port */ + + +extern u_char *get_tcp_port(u_int port) +{ + static gchar str[3][MAXNAMELEN]; + static gchar *cur; + + if (!g_resolving_actif) { + if (cur == &str[0][0]) { + cur = &str[1][0]; + } else if (cur == &str[1][0]) { + cur = &str[2][0]; + } else { + cur = &str[0][0]; + } + sprintf(cur, "%d", port); + return cur; + } + + return serv_name_lookup(port, IPPROTO_TCP); + +} /* get_tcp_port */ + |