diff options
Diffstat (limited to 'libcli/dns/dns_hosts_file.c')
| -rw-r--r-- | libcli/dns/dns_hosts_file.c | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/libcli/dns/dns_hosts_file.c b/libcli/dns/dns_hosts_file.c new file mode 100644 index 0000000000..94d1d9704a --- /dev/null +++ b/libcli/dns/dns_hosts_file.c @@ -0,0 +1,415 @@ +/* + Unix SMB/CIFS implementation. + + read a file containing DNS names, types and IP addresses + + Copyright (C) Andrew Tridgell 1994-1998 + Copyright (C) Jeremy Allison 2007 + Copyright (C) Andrew Bartlett 2009-2011 + + 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 3 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, see <http://www.gnu.org/licenses/>. +*/ + +/* The purpose of this file is to read the file generated by the samba_dnsupdate script */ + +#include "includes.h" +#include "lib/util/xfile.h" +#include "lib/util/util_net.h" +#include "system/filesys.h" +#include "system/network.h" +#include "libcli/nbt/libnbt.h" +#include "libcli/dns/dns.h" + +#ifdef strcasecmp +#undef strcasecmp +#endif + +/******************************************************** + Start parsing the dns_hosts_file file. +*********************************************************/ + +static XFILE *startdns_hosts_file(const char *fname) +{ + XFILE *fp = x_fopen(fname,O_RDONLY, 0); + if (!fp) { + DEBUG(4,("startdns_hosts_file: Can't open dns_hosts_file file %s. " + "Error was %s\n", + fname, strerror(errno))); + return NULL; + } + return fp; +} + +/******************************************************** + Parse the next line in the dns_hosts_file file. +*********************************************************/ + +static bool getdns_hosts_fileent(TALLOC_CTX *ctx, XFILE *fp, char **pp_name, char **pp_name_type, + char **pp_next_name, + struct sockaddr_storage *pss, uint32_t *p_port) +{ + char line[1024]; + + *pp_name = NULL; + *pp_name_type = NULL; + *pp_next_name = NULL; + *p_port = 0; + + while(!x_feof(fp) && !x_ferror(fp)) { + char *name_type = NULL; + char *name = NULL; + char *next_name = NULL; + char *ip = NULL; + char *port = NULL; + + const char *ptr; + int count = 0; + + if (!fgets_slash(line,sizeof(line),fp)) { + continue; + } + + if (*line == '#') { + continue; + } + + ptr = line; + + if (next_token_talloc(ctx, &ptr, &name_type, NULL)) + ++count; + if (next_token_talloc(ctx, &ptr, &name, NULL)) + ++count; + if (name_type && strcasecmp(name_type, "A") == 0) { + if (next_token_talloc(ctx, &ptr, &ip, NULL)) + ++count; + } else if (name_type && strcasecmp(name_type, "SRV") == 0) { + if (next_token_talloc(ctx, &ptr, &next_name, NULL)) + ++count; + if (next_token_talloc(ctx, &ptr, &port, NULL)) + ++count; + } else if (name_type && strcasecmp(name_type, "CNAME") == 0) { + if (next_token_talloc(ctx, &ptr, &next_name, NULL)) + ++count; + } + if (count <= 0) + continue; + + if (strcasecmp(name_type, "A") == 0) { + if (count != 3) { + DEBUG(0,("getdns_hosts_fileent: Ill formed hosts A record [%s]\n", + line)); + continue; + } + DEBUG(4, ("getdns_hosts_fileent: host entry: %s %s %s\n", + name_type, name, ip)); + if (!interpret_string_addr(pss, ip, AI_NUMERICHOST)) { + DEBUG(0,("getdns_hosts_fileent: invalid address " + "%s.\n", ip)); + } + + } else if (strcasecmp(name_type, "SRV") == 0) { + if (count != 4) { + DEBUG(0,("getdns_hosts_fileent: Ill formed hosts SRV record [%s]\n", + line)); + continue; + } + *p_port = strtoul(port, NULL, 10); + if (*p_port == UINT32_MAX) { + DEBUG(0, ("getdns_hosts_fileent: Ill formed hosts SRV record [%s] (invalid port: %s)\n", + line, port)); + continue; + } + DEBUG(4, ("getdns_hosts_fileent: host entry: %s %s %s %u\n", + name_type, name, next_name, (unsigned int)*p_port)); + *pp_next_name = talloc_strdup(ctx, next_name); + if (!*pp_next_name) { + return false; + } + } else if (strcasecmp(name_type, "CNAME") == 0) { + if (count != 3) { + DEBUG(0,("getdns_hosts_fileent: Ill formed hosts CNAME record [%s]\n", + line)); + continue; + } + DEBUG(4, ("getdns_hosts_fileent: host entry: %s %s %s\n", + name_type, name, next_name)); + *pp_next_name = talloc_strdup(ctx, next_name); + if (!*pp_next_name) { + return false; + } + } else { + DEBUG(0,("getdns_hosts_fileent: unknown type %s\n", name_type)); + continue; + } + + *pp_name = talloc_strdup(ctx, name); + if (!*pp_name) { + return false; + } + + *pp_name_type = talloc_strdup(ctx, name_type); + if (!*pp_name_type) { + return false; + } + return true; + } + + return false; +} + +/******************************************************** + Finish parsing the dns_hosts_file file. +*********************************************************/ + +static void enddns_hosts_file(XFILE *fp) +{ + x_fclose(fp); +} + +/******************************************************** + Resolve via "dns_hosts" method. +*********************************************************/ + +static NTSTATUS resolve_dns_hosts_file_as_dns_rr_recurse(const char *dns_hosts_file, + const char *name, bool srv_lookup, + int level, uint32_t port, + TALLOC_CTX *mem_ctx, + struct dns_rr_srv **return_rr, + int *return_count) +{ + /* + * "dns_hosts" means parse the local dns_hosts file. + */ + + XFILE *fp; + char *host_name = NULL; + char *name_type = NULL; + char *next_name = NULL; + struct sockaddr_storage return_ss; + uint32_t srv_port; + NTSTATUS status = NT_STATUS_OBJECT_NAME_NOT_FOUND; + TALLOC_CTX *ctx = NULL; + TALLOC_CTX *ip_list_ctx = NULL; + struct dns_rr_srv *rr = NULL; + + *return_rr = NULL; + + /* Don't recurse forever, even on our own flat files */ + if (level > 11) { + DEBUG(0, ("resolve_dns_hosts_file recursion limit reached looking up %s!\n", name)); + return status; + } + + *return_count = 0; + + DEBUG(3,("resolve_dns_hosts: (%d) " + "Attempting %s dns_hosts lookup for name %s\n", + level, srv_lookup ? "SRV" : "A", name)); + + fp = startdns_hosts_file(dns_hosts_file); + + if ( fp == NULL ) + return NT_STATUS_OBJECT_NAME_NOT_FOUND; + + ip_list_ctx = talloc_new(mem_ctx); + if (!ip_list_ctx) { + enddns_hosts_file(fp); + return NT_STATUS_NO_MEMORY; + } + + ctx = talloc_new(ip_list_ctx); + if (!ctx) { + talloc_free(ip_list_ctx); + enddns_hosts_file(fp); + return NT_STATUS_NO_MEMORY; + } + + while (getdns_hosts_fileent(ctx, fp, &host_name, &name_type, &next_name, &return_ss, &srv_port)) { + if (!strequal(name, host_name)) { + /* continue at the bottom of the loop */ + } else if (srv_lookup) { + if (strcasecmp(name_type, "SRV") == 0) { + NTSTATUS status_recurse; + struct dns_rr_srv *tmp_rr; + int tmp_count = 0; + /* we only accept one host name per SRV entry */ + status_recurse + = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, next_name, + false, + level + 1, srv_port, + ip_list_ctx, &tmp_rr, + &tmp_count); + if (NT_STATUS_EQUAL(status_recurse, NT_STATUS_OBJECT_NAME_NOT_FOUND)) { + /* Don't fail on a dangling SRV record */ + } else if (!NT_STATUS_IS_OK(status_recurse)) { + enddns_hosts_file(fp); + talloc_free(ip_list_ctx); + return status_recurse; + } else if (tmp_count != 1) { + status = NT_STATUS_OBJECT_NAME_NOT_FOUND; + } else { + status = status_recurse; + rr = talloc_realloc(ip_list_ctx, rr, struct dns_rr_srv, (*return_count) + 1); + if (!rr) { + enddns_hosts_file(fp); + return NT_STATUS_NO_MEMORY; + } + talloc_steal(rr, tmp_rr); + rr[*return_count] = *tmp_rr; + *return_count = (*return_count) + 1; + } + } + } else if (strcasecmp(name_type, "CNAME") == 0) { + /* we only accept one host name per CNAME */ + enddns_hosts_file(fp); + status = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, next_name, false, + level + 1, port, + mem_ctx, return_rr, return_count); + talloc_free(ip_list_ctx); + return status; + } else if (strcasecmp(name_type, "A") == 0) { + if (*return_count == 0) { + /* We are happy to keep looking for other possible A record matches */ + rr = talloc_zero(ip_list_ctx, + struct dns_rr_srv); + + if (rr == NULL) { + TALLOC_FREE(ctx); + enddns_hosts_file(fp); + DEBUG(3,("resolve_dns_hosts: talloc_realloc fail !\n")); + return NT_STATUS_NO_MEMORY; + } + + rr->hostname = talloc_strdup(rr, host_name); + + if (rr->hostname == NULL) { + TALLOC_FREE(ctx); + enddns_hosts_file(fp); + DEBUG(3,("resolve_dns_hosts: talloc_realloc fail !\n")); + return NT_STATUS_NO_MEMORY; + } + rr->port = port; + + *return_count = 1; + } + + /* Set the specified port (possibly from a SRV lookup) into the structure we return */ + set_sockaddr_port((struct sockaddr *)&return_ss, port); + + /* We are happy to keep looking for other possible A record matches */ + rr->ss_s = talloc_realloc(rr, rr->ss_s, + struct sockaddr_storage, + rr->num_ips + 1); + + if (rr->ss_s == NULL) { + TALLOC_FREE(ctx); + enddns_hosts_file(fp); + DEBUG(3,("resolve_dns_hosts: talloc_realloc fail !\n")); + return NT_STATUS_NO_MEMORY; + } + + rr->ss_s[rr->num_ips] = return_ss; + rr->num_ips += 1; + + /* we found something */ + status = NT_STATUS_OK; + } + + TALLOC_FREE(ctx); + ctx = talloc_new(mem_ctx); + if (!ctx) { + enddns_hosts_file(fp); + return NT_STATUS_NO_MEMORY; + } + } + + *return_rr = talloc_steal(mem_ctx, rr); + TALLOC_FREE(ip_list_ctx); + enddns_hosts_file(fp); + return status; +} + +/******************************************************** + Resolve via "dns_hosts_file" method, returning a list of sockaddr_storage values +*********************************************************/ + +NTSTATUS resolve_dns_hosts_file_as_sockaddr(const char *dns_hosts_file, + const char *name, bool srv_lookup, + TALLOC_CTX *mem_ctx, + struct sockaddr_storage **return_iplist, + int *return_count) +{ + NTSTATUS status; + struct dns_rr_srv *dns_rr = NULL; + int i, j, rr_count = 0; + + *return_iplist = NULL; + *return_count = 0; + + status = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, name, srv_lookup, + 0, 0, + mem_ctx, &dns_rr, &rr_count); + if (!NT_STATUS_IS_OK(status)) { + DEBUG(3,("resolve_dns_hosts (sockaddr): " + "failed to obtain %s result records for for name %s: %s\n", + srv_lookup ? "SRV" : "A", name, nt_errstr(status))); + return status; + } + + for (i=0; i < rr_count; i++) { + *return_iplist = talloc_realloc(mem_ctx, *return_iplist, struct sockaddr_storage, *return_count + dns_rr[i].num_ips); + if (!*return_iplist) { + return NT_STATUS_NO_MEMORY; + } + for (j=0; j < dns_rr[i].num_ips; j++) { + (*return_iplist)[*return_count] = dns_rr[i].ss_s[j]; + *return_count = *return_count + 1; + } + } + DEBUG(3,("resolve_dns_hosts (sockaddr): " + "Found %d results for for name %s\n", + *return_count, name)); + + return NT_STATUS_OK; +} + +/******************************************************** + Resolve via "dns_hosts_file" method, returning struct dns_rr_srv +*********************************************************/ + +NTSTATUS resolve_dns_hosts_file_as_dns_rr(const char *dns_hosts_file, + const char *name, bool srv_lookup, + TALLOC_CTX *mem_ctx, + struct dns_rr_srv **return_rr, + int *return_count) +{ + NTSTATUS status; + *return_rr = NULL; + *return_count = 0; + + status = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, name, srv_lookup, + 0, 0, + mem_ctx, return_rr, return_count); + + if (NT_STATUS_IS_OK(status)) { + DEBUG(3,("resolve_dns_hosts (dns_rr): " + "Found %d %s result records for for name %s\n", + *return_count, srv_lookup ? "SRV" : "A", name)); + } else { + DEBUG(3,("resolve_dns_hosts (dns_rr): " + "failed to obtain %s result records for for name %s: %s\n", + srv_lookup ? "SRV" : "A", name, nt_errstr(status))); + } + return status; +} |