1/* 2 Unix SMB/CIFS implementation. 3 4 low level socket handling for nbt dgram requests (UDP138) 5 6 Copyright (C) Andrew Tridgell 2005 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. 20*/ 21 22#include "includes.h" 23#include "lib/events/events.h" 24#include "../lib/util/dlinklist.h" 25#include "libcli/dgram/libdgram.h" 26#include "lib/socket/socket.h" 27#include "librpc/gen_ndr/ndr_nbt.h" 28 29 30/* 31 handle recv events on a nbt dgram socket 32*/ 33static void dgm_socket_recv(struct nbt_dgram_socket *dgmsock) 34{ 35 TALLOC_CTX *tmp_ctx = talloc_new(dgmsock); 36 NTSTATUS status; 37 struct socket_address *src; 38 DATA_BLOB blob; 39 size_t nread, dsize; 40 struct nbt_dgram_packet *packet; 41 const char *mailslot_name; 42 enum ndr_err_code ndr_err; 43 44 status = socket_pending(dgmsock->sock, &dsize); 45 if (!NT_STATUS_IS_OK(status)) { 46 talloc_free(tmp_ctx); 47 return; 48 } 49 50 blob = data_blob_talloc(tmp_ctx, NULL, dsize); 51 if (blob.data == NULL) { 52 talloc_free(tmp_ctx); 53 return; 54 } 55 56 status = socket_recvfrom(dgmsock->sock, blob.data, blob.length, &nread, 57 tmp_ctx, &src); 58 if (!NT_STATUS_IS_OK(status)) { 59 talloc_free(tmp_ctx); 60 return; 61 } 62 blob.length = nread; 63 64 DEBUG(2,("Received dgram packet of length %d from %s:%d\n", 65 (int)blob.length, src->addr, src->port)); 66 67 packet = talloc(tmp_ctx, struct nbt_dgram_packet); 68 if (packet == NULL) { 69 talloc_free(tmp_ctx); 70 return; 71 } 72 73 /* parse the request */ 74 ndr_err = ndr_pull_struct_blob(&blob, packet, dgmsock->iconv_convenience, packet, 75 (ndr_pull_flags_fn_t)ndr_pull_nbt_dgram_packet); 76 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { 77 status = ndr_map_error2ntstatus(ndr_err); 78 DEBUG(2,("Failed to parse incoming NBT DGRAM packet - %s\n", 79 nt_errstr(status))); 80 talloc_free(tmp_ctx); 81 return; 82 } 83 84 /* if this is a mailslot message, then see if we can dispatch it to a handler */ 85 mailslot_name = dgram_mailslot_name(packet); 86 if (mailslot_name) { 87 struct dgram_mailslot_handler *dgmslot; 88 dgmslot = dgram_mailslot_find(dgmsock, mailslot_name); 89 if (dgmslot) { 90 dgmslot->handler(dgmslot, packet, src); 91 } else { 92 DEBUG(2,("No mailslot handler for '%s'\n", mailslot_name)); 93 } 94 } else { 95 /* dispatch if there is a general handler */ 96 if (dgmsock->incoming.handler) { 97 dgmsock->incoming.handler(dgmsock, packet, src); 98 } 99 } 100 101 talloc_free(tmp_ctx); 102} 103 104 105/* 106 handle send events on a nbt dgram socket 107*/ 108static void dgm_socket_send(struct nbt_dgram_socket *dgmsock) 109{ 110 struct nbt_dgram_request *req; 111 NTSTATUS status; 112 113 while ((req = dgmsock->send_queue)) { 114 size_t len; 115 116 len = req->encoded.length; 117 status = socket_sendto(dgmsock->sock, &req->encoded, &len, 118 req->dest); 119 if (NT_STATUS_IS_ERR(status)) { 120 DEBUG(3,("Failed to send datagram of length %u to %s:%d: %s\n", 121 (unsigned)req->encoded.length, req->dest->addr, req->dest->port, 122 nt_errstr(status))); 123 DLIST_REMOVE(dgmsock->send_queue, req); 124 talloc_free(req); 125 continue; 126 } 127 128 if (!NT_STATUS_IS_OK(status)) return; 129 130 DLIST_REMOVE(dgmsock->send_queue, req); 131 talloc_free(req); 132 } 133 134 EVENT_FD_NOT_WRITEABLE(dgmsock->fde); 135 return; 136} 137 138 139/* 140 handle fd events on a nbt_dgram_socket 141*/ 142static void dgm_socket_handler(struct tevent_context *ev, struct tevent_fd *fde, 143 uint16_t flags, void *private_data) 144{ 145 struct nbt_dgram_socket *dgmsock = talloc_get_type(private_data, 146 struct nbt_dgram_socket); 147 if (flags & EVENT_FD_WRITE) { 148 dgm_socket_send(dgmsock); 149 } 150 if (flags & EVENT_FD_READ) { 151 dgm_socket_recv(dgmsock); 152 } 153} 154 155/* 156 initialise a nbt_dgram_socket. The event_ctx is optional, if provided 157 then operations will use that event context 158*/ 159struct nbt_dgram_socket *nbt_dgram_socket_init(TALLOC_CTX *mem_ctx, 160 struct tevent_context *event_ctx, 161 struct smb_iconv_convenience *iconv_convenience) 162{ 163 struct nbt_dgram_socket *dgmsock; 164 NTSTATUS status; 165 166 dgmsock = talloc(mem_ctx, struct nbt_dgram_socket); 167 if (dgmsock == NULL) goto failed; 168 169 dgmsock->event_ctx = event_ctx; 170 if (dgmsock->event_ctx == NULL) goto failed; 171 172 status = socket_create("ip", SOCKET_TYPE_DGRAM, &dgmsock->sock, 0); 173 if (!NT_STATUS_IS_OK(status)) goto failed; 174 175 socket_set_option(dgmsock->sock, "SO_BROADCAST", "1"); 176 177 talloc_steal(dgmsock, dgmsock->sock); 178 179 dgmsock->fde = event_add_fd(dgmsock->event_ctx, dgmsock, 180 socket_get_fd(dgmsock->sock), 0, 181 dgm_socket_handler, dgmsock); 182 183 dgmsock->send_queue = NULL; 184 dgmsock->incoming.handler = NULL; 185 dgmsock->mailslot_handlers = NULL; 186 dgmsock->iconv_convenience = iconv_convenience; 187 188 return dgmsock; 189 190failed: 191 talloc_free(dgmsock); 192 return NULL; 193} 194 195 196/* 197 setup a handler for generic incoming requests 198*/ 199NTSTATUS dgram_set_incoming_handler(struct nbt_dgram_socket *dgmsock, 200 void (*handler)(struct nbt_dgram_socket *, 201 struct nbt_dgram_packet *, 202 struct socket_address *), 203 void *private_data) 204{ 205 dgmsock->incoming.handler = handler; 206 dgmsock->incoming.private_data = private_data; 207 EVENT_FD_READABLE(dgmsock->fde); 208 return NT_STATUS_OK; 209} 210 211 212/* 213 queue a datagram for send 214*/ 215NTSTATUS nbt_dgram_send(struct nbt_dgram_socket *dgmsock, 216 struct nbt_dgram_packet *packet, 217 struct socket_address *dest) 218{ 219 struct nbt_dgram_request *req; 220 NTSTATUS status = NT_STATUS_NO_MEMORY; 221 enum ndr_err_code ndr_err; 222 223 req = talloc(dgmsock, struct nbt_dgram_request); 224 if (req == NULL) goto failed; 225 226 req->dest = dest; 227 if (talloc_reference(req, dest) == NULL) goto failed; 228 229 ndr_err = ndr_push_struct_blob(&req->encoded, req, dgmsock->iconv_convenience, packet, 230 (ndr_push_flags_fn_t)ndr_push_nbt_dgram_packet); 231 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { 232 status = ndr_map_error2ntstatus(ndr_err); 233 goto failed; 234 } 235 236 DLIST_ADD_END(dgmsock->send_queue, req, struct nbt_dgram_request *); 237 238 EVENT_FD_WRITEABLE(dgmsock->fde); 239 240 return NT_STATUS_OK; 241 242failed: 243 talloc_free(req); 244 return status; 245} 246