Fri Aug 24 02:22:09 2007

Asterisk developer's documentation


acl.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2006, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief Various sorts of access control
00022  *
00023  * \author Mark Spencer <markster@digium.com>
00024  */
00025 
00026 #include "asterisk.h"
00027 
00028 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
00029 
00030 #include <stdio.h>
00031 #include <stdlib.h>
00032 #include <string.h>
00033 #include <sys/time.h>
00034 #include <signal.h>
00035 #include <errno.h>
00036 #include <unistd.h>
00037 #include <netinet/in.h>
00038 #include <arpa/inet.h>
00039 #include <sys/socket.h>
00040 #include <netdb.h>
00041 #include <net/if.h>
00042 #include <netinet/in.h>
00043 #include <netinet/in_systm.h>
00044 #include <netinet/ip.h>
00045 #include <sys/ioctl.h>
00046 
00047 #if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
00048 #include <fcntl.h>
00049 #include <net/route.h>
00050 #endif
00051 
00052 #if defined(SOLARIS)
00053 #include <sys/sockio.h>
00054 #endif
00055 
00056 /* netinet/ip.h may not define the following (See RFCs 791 and 1349) */
00057 #if !defined(IPTOS_LOWCOST)
00058 #define       IPTOS_LOWCOST           0x02
00059 #endif
00060 
00061 #if !defined(IPTOS_MINCOST)
00062 #define       IPTOS_MINCOST           IPTOS_LOWCOST
00063 #endif
00064 
00065 #include "asterisk/acl.h"
00066 #include "asterisk/logger.h"
00067 #include "asterisk/channel.h"
00068 #include "asterisk/options.h"
00069 #include "asterisk/utils.h"
00070 #include "asterisk/lock.h"
00071 #include "asterisk/srv.h"
00072 
00073 struct ast_ha {
00074    /* Host access rule */
00075    struct in_addr netaddr;
00076    struct in_addr netmask;
00077    int sense;
00078    struct ast_ha *next;
00079 };
00080 
00081 /* Default IP - if not otherwise set, don't breathe garbage */
00082 static struct in_addr __ourip = { .s_addr = 0x00000000, };
00083 
00084 struct my_ifreq {
00085    char ifrn_name[IFNAMSIZ];  /* Interface name, e.g. "eth0", "ppp0", etc.  */
00086    struct sockaddr_in ifru_addr;
00087 };
00088 
00089 /* Free HA structure */
00090 void ast_free_ha(struct ast_ha *ha)
00091 {
00092    struct ast_ha *hal;
00093    while (ha) {
00094       hal = ha;
00095       ha = ha->next;
00096       free(hal);
00097    }
00098 }
00099 
00100 /* Copy HA structure */
00101 static void ast_copy_ha(struct ast_ha *from, struct ast_ha *to)
00102 {
00103    memcpy(&to->netaddr, &from->netaddr, sizeof(from->netaddr));
00104    memcpy(&to->netmask, &from->netmask, sizeof(from->netmask));
00105    to->sense = from->sense;
00106 }
00107 
00108 /* Create duplicate of ha structure */
00109 static struct ast_ha *ast_duplicate_ha(struct ast_ha *original)
00110 {
00111    struct ast_ha *new_ha;
00112 
00113    if ((new_ha = ast_malloc(sizeof(*new_ha)))) {
00114       /* Copy from original to new object */
00115       ast_copy_ha(original, new_ha);
00116    }
00117 
00118    return new_ha;
00119 }
00120 
00121 /* Create duplicate HA link list */
00122 /*  Used in chan_sip2 templates */
00123 struct ast_ha *ast_duplicate_ha_list(struct ast_ha *original)
00124 {
00125    struct ast_ha *start = original;
00126    struct ast_ha *ret = NULL;
00127    struct ast_ha *link, *prev = NULL;
00128 
00129    while (start) {
00130       link = ast_duplicate_ha(start);  /* Create copy of this object */
00131       if (prev)
00132          prev->next = link;      /* Link previous to this object */
00133 
00134       if (!ret)
00135          ret = link;    /* Save starting point */
00136 
00137       start = start->next;    /* Go to next object */
00138       prev = link;         /* Save pointer to this object */
00139    }
00140    return ret;             /* Return start of list */
00141 }
00142 
00143 struct ast_ha *ast_append_ha(char *sense, char *stuff, struct ast_ha *path)
00144 {
00145    struct ast_ha *ha;
00146    char *nm = "255.255.255.255";
00147    char tmp[256];
00148    struct ast_ha *prev = NULL;
00149    struct ast_ha *ret;
00150    int x, z;
00151    unsigned int y;
00152 
00153    ret = path;
00154    while (path) {
00155       prev = path;
00156       path = path->next;
00157    }
00158    if ((ha = ast_malloc(sizeof(*ha)))) {
00159       ast_copy_string(tmp, stuff, sizeof(tmp));
00160       nm = strchr(tmp, '/');
00161       if (!nm) {
00162          nm = "255.255.255.255";
00163       } else {
00164          *nm = '\0';
00165          nm++;
00166       }
00167       if (!strchr(nm, '.')) {
00168          if ((sscanf(nm, "%d", &x) == 1) && (x >= 0) && (x <= 32)) {
00169             y = 0;
00170             for (z = 0; z < x; z++) {
00171                y >>= 1;
00172                y |= 0x80000000;
00173             }
00174             ha->netmask.s_addr = htonl(y);
00175          }
00176       } else if (!inet_aton(nm, &ha->netmask)) {
00177          ast_log(LOG_WARNING, "%s is not a valid netmask\n", nm);
00178          free(ha);
00179          return ret;
00180       }
00181       if (!inet_aton(tmp, &ha->netaddr)) {
00182          ast_log(LOG_WARNING, "%s is not a valid IP\n", tmp);
00183          free(ha);
00184          return ret;
00185       }
00186       ha->netaddr.s_addr &= ha->netmask.s_addr;
00187       if (!strncasecmp(sense, "p", 1)) {
00188          ha->sense = AST_SENSE_ALLOW;
00189       } else {
00190          ha->sense = AST_SENSE_DENY;
00191       }
00192       ha->next = NULL;
00193       if (prev) {
00194          prev->next = ha;
00195       } else {
00196          ret = ha;
00197       }
00198    }
00199    if (option_debug)
00200       ast_log(LOG_DEBUG, "%s/%s appended to acl for peer\n", stuff, nm);
00201    return ret;
00202 }
00203 
00204 int ast_apply_ha(struct ast_ha *ha, struct sockaddr_in *sin)
00205 {
00206    /* Start optimistic */
00207    int res = AST_SENSE_ALLOW;
00208    while (ha) {
00209       char iabuf[INET_ADDRSTRLEN];
00210       char iabuf2[INET_ADDRSTRLEN];
00211       /* DEBUG */
00212       ast_copy_string(iabuf, ast_inet_ntoa(sin->sin_addr), sizeof(iabuf));
00213       ast_copy_string(iabuf2, ast_inet_ntoa(ha->netaddr), sizeof(iabuf2));
00214       if (option_debug)
00215          ast_log(LOG_DEBUG, "##### Testing %s with %s\n", iabuf, iabuf2);
00216       /* For each rule, if this address and the netmask = the net address
00217          apply the current rule */
00218       if ((sin->sin_addr.s_addr & ha->netmask.s_addr) == ha->netaddr.s_addr)
00219          res = ha->sense;
00220       ha = ha->next;
00221    }
00222    return res;
00223 }
00224 
00225 int ast_get_ip_or_srv(struct sockaddr_in *sin, const char *value, const char *service)
00226 {
00227    struct hostent *hp;
00228    struct ast_hostent ahp;
00229    char srv[256];
00230    char host[256];
00231    int tportno = ntohs(sin->sin_port);
00232    if (inet_aton(value, &sin->sin_addr))
00233       return 0;
00234    if (service) {
00235       snprintf(srv, sizeof(srv), "%s.%s", service, value);
00236       if (ast_get_srv(NULL, host, sizeof(host), &tportno, srv) > 0) {
00237          sin->sin_port = htons(tportno);
00238          value = host;
00239       }
00240    }
00241    hp = ast_gethostbyname(value, &ahp);
00242    if (hp) {
00243       memcpy(&sin->sin_addr, hp->h_addr, sizeof(sin->sin_addr));
00244    } else {
00245       ast_log(LOG_WARNING, "Unable to lookup '%s'\n", value);
00246       return -1;
00247    }
00248    return 0;
00249 }
00250 
00251 struct dscp_codepoint {
00252    char *name;
00253    unsigned int space;
00254 };
00255 
00256 /* IANA registered DSCP codepoints */
00257 
00258 static const struct dscp_codepoint dscp_pool1[] = {
00259    { "CS0", 0x00 },
00260    { "CS1", 0x08 },
00261    { "CS2", 0x10 },
00262    { "CS3", 0x18 },
00263    { "CS4", 0x20 },
00264    { "CS5", 0x28 },
00265    { "CS6", 0x30 },
00266    { "CS7", 0x38 },
00267    { "AF11", 0x0A },
00268    { "AF12", 0x0C },
00269    { "AF13", 0x0E },
00270    { "AF21", 0x12 },
00271    { "AF22", 0x14 },
00272    { "AF23", 0x16 },
00273    { "AF31", 0x1A },
00274    { "AF32", 0x1C },
00275    { "AF33", 0x1E },
00276    { "AF41", 0x22 },
00277    { "AF42", 0x24 },
00278    { "AF43", 0x26 },
00279    { "EF", 0x2E },
00280 };
00281 
00282 int ast_str2tos(const char *value, unsigned int *tos)
00283 {
00284    int fval;
00285    unsigned int x;
00286 
00287    if (sscanf(value, "%i", &fval) == 1) {
00288       *tos = fval & 0xFF;
00289       return 0;
00290    }
00291 
00292    for (x = 0; x < sizeof(dscp_pool1) / sizeof(dscp_pool1[0]); x++) {
00293       if (!strcasecmp(value, dscp_pool1[x].name)) {
00294          *tos = dscp_pool1[x].space << 2;
00295          return 0;
00296       }
00297    }
00298 
00299    if (!strcasecmp(value, "lowdelay"))
00300       *tos = IPTOS_LOWDELAY;
00301    else if (!strcasecmp(value, "throughput"))
00302       *tos = IPTOS_THROUGHPUT;
00303    else if (!strcasecmp(value, "reliability"))
00304       *tos = IPTOS_RELIABILITY;
00305    else if (!strcasecmp(value, "mincost"))
00306       *tos = IPTOS_MINCOST;
00307    else if (!strcasecmp(value, "none"))
00308       *tos = 0;
00309    else
00310       return -1;
00311 
00312    ast_log(LOG_WARNING, "TOS value %s is deprecated. Please see doc/ip-tos.txt for more information.\n", value);
00313 
00314    return 0;
00315 }
00316 
00317 const char *ast_tos2str(unsigned int tos)
00318 {
00319    unsigned int x;
00320 
00321    switch (tos) {
00322    case 0:
00323       return "none";
00324    case IPTOS_LOWDELAY:
00325       return "lowdelay";
00326    case IPTOS_THROUGHPUT:
00327       return "throughput";
00328    case IPTOS_RELIABILITY:
00329       return "reliability";
00330    case IPTOS_MINCOST:
00331       return "mincost";
00332    default:
00333       for (x = 0; x < sizeof(dscp_pool1) / sizeof(dscp_pool1[0]); x++) {
00334          if (dscp_pool1[x].space == (tos >> 2))
00335             return dscp_pool1[x].name;
00336       }
00337    }
00338 
00339    return "unknown";
00340 }
00341 
00342 int ast_get_ip(struct sockaddr_in *sin, const char *value)
00343 {
00344    return ast_get_ip_or_srv(sin, value, NULL);
00345 }
00346 
00347 /* iface is the interface (e.g. eth0); address is the return value */
00348 int ast_lookup_iface(char *iface, struct in_addr *address)
00349 {
00350    int mysock, res = 0;
00351    struct my_ifreq ifreq;
00352 
00353    memset(&ifreq, 0, sizeof(ifreq));
00354    ast_copy_string(ifreq.ifrn_name, iface, sizeof(ifreq.ifrn_name));
00355 
00356    mysock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
00357    res = ioctl(mysock, SIOCGIFADDR, &ifreq);
00358 
00359    close(mysock);
00360    if (res < 0) {
00361       ast_log(LOG_WARNING, "Unable to get IP of %s: %s\n", iface, strerror(errno));
00362       memcpy((char *)address, (char *)&__ourip, sizeof(__ourip));
00363       return -1;
00364    } else {
00365       memcpy((char *)address, (char *)&ifreq.ifru_addr.sin_addr, sizeof(ifreq.ifru_addr.sin_addr));
00366       return 0;
00367    }
00368 }
00369 
00370 int ast_ouraddrfor(struct in_addr *them, struct in_addr *us)
00371 {
00372    int s;
00373    struct sockaddr_in sin;
00374    socklen_t slen;
00375 
00376    s = socket(PF_INET, SOCK_DGRAM, 0);
00377    if (s < 0) {
00378       ast_log(LOG_WARNING, "Cannot create socket\n");
00379       return -1;
00380    }
00381    sin.sin_family = AF_INET;
00382    sin.sin_port = 5060;
00383    sin.sin_addr = *them;
00384    if (connect(s, (struct sockaddr *)&sin, sizeof(sin))) {
00385       ast_log(LOG_WARNING, "Cannot connect\n");
00386       close(s);
00387       return -1;
00388    }
00389    slen = sizeof(sin);
00390    if (getsockname(s, (struct sockaddr *)&sin, &slen)) {
00391       ast_log(LOG_WARNING, "Cannot get socket name\n");
00392       close(s);
00393       return -1;
00394    }
00395    close(s);
00396    *us = sin.sin_addr;
00397    return 0;
00398 }
00399 
00400 int ast_find_ourip(struct in_addr *ourip, struct sockaddr_in bindaddr)
00401 {
00402    char ourhost[MAXHOSTNAMELEN] = "";
00403    struct ast_hostent ahp;
00404    struct hostent *hp;
00405    struct in_addr saddr;
00406 
00407    /* just use the bind address if it is nonzero */
00408    if (ntohl(bindaddr.sin_addr.s_addr)) {
00409       memcpy(ourip, &bindaddr.sin_addr, sizeof(*ourip));
00410       return 0;
00411    }
00412    /* try to use our hostname */
00413    if (gethostname(ourhost, sizeof(ourhost) - 1)) {
00414       ast_log(LOG_WARNING, "Unable to get hostname\n");
00415    } else {
00416       hp = ast_gethostbyname(ourhost, &ahp);
00417       if (hp) {
00418          memcpy(ourip, hp->h_addr, sizeof(*ourip));
00419          return 0;
00420       }
00421    }
00422    /* A.ROOT-SERVERS.NET. */
00423    if (inet_aton("198.41.0.4", &saddr) && !ast_ouraddrfor(&saddr, ourip))
00424       return 0;
00425    return -1;
00426 }
00427 

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