vde-2/libvdeplug/libvdeplug.c

   1 /*
   2  * libvdeplug - A library to connect to a VDE Switch.
   3  * Copyright (C) 2006 Renzo Davoli, University of Bologna
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Lesser General Public License as published by
   7  * the Free Software Foundation version 2.1 of the License, or (at
   8  * your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA
  18  */
  19
  20 #include "libvdeplug.h"
  21 #include <errno.h>
  22 #include <sys/socket.h>
  23 #include <sys/un.h>
  24 #include <stdint.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <pwd.h>
  28 #include <grp.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <unistd.h>
  32 #include <string.h>
  33
  34 /* IPNVDE - Kernel VDE
  35 */
  36 #define USE_IPNVDE
  37
  38 #ifdef USE_IPNVDE
  39 #include <af_ipnvde.h>
  40 #endif
  41
  42 #ifndef VDESTDSOCK
  43 #define VDESTDSOCK  "/var/run/vde.ctl"
  44 #define VDETMPSOCK  "/tmp/vde.ctl"
  45 #endif
  46
  47 struct vdeconn {
  48         int fdctl;
  49         int fddata;
  50         struct sockaddr_un inpath;
  51 };
  52
  53 #define SWITCH_MAGIC 0xfeedface
  54 #define MAXDESCR 128
  55
  56 enum request_type { REQ_NEW_CONTROL };
  57
  58 struct request_v3 {
  59         uint32_t magic;
  60         uint32_t version;
  61         enum request_type type;
  62         struct sockaddr_un sock;
  63         char description[MAXDESCR];
  64 };
  65
  66 VDECONN *vde_open_real(char *sockname,char *descr,int interface_version,
  67                 struct vde_open_args *open_args)
  68 {
  69         struct vdeconn *conn;
  70         struct passwd *callerpwd;
  71         struct request_v3 req;
  72         int pid = getpid();
  73         static struct sockaddr_un sockun;
  74         static struct sockaddr_un dataout;
  75         int port=0;
  76         char *group=NULL;
  77         int sockno=0;
  78         int res;
  79         mode_t mode=0700;
  80
  81         if (open_args != NULL) {
  82                 if (interface_version == 1) {
  83                         port=open_args->port;
  84                         group=open_args->group;
  85                         mode=open_args->mode;
  86                 }
  87                 else {
  88                         errno=EINVAL;
  89                         return NULL;
  90                 }
  91         }
  92
  93         if ((conn=calloc(1,sizeof(struct vdeconn)))==NULL)
  94         {
  95                 errno=ENOMEM;
  96                 return NULL;
  97         }
  98         //get the login name
  99         callerpwd=getpwuid(getuid());
 100         if (sockname == NULL || *sockname == '\0')
 101                 sockname=VDESTDSOCK;
 102         else {
 103                 char *split;
 104                 if(sockname[strlen(sockname)-1] == ']' && (split=rindex(sockname,'[')) != NULL) {
 105                         *split=0;
 106                         split++;
 107                         port=atoi(split);
 108                         if (*sockname==0) sockname=VDESTDSOCK;
 109                 }
 110         }
 111 #ifdef USE_IPNVDE
 112         if((conn->fddata = socket(AF_IPNVDE,SOCK_RAW,IPNVDE_ANY)) >= 0) {
 113                 /* IPNVDE service exists */
 114                 sockun.sun_family = AF_IPNVDE;
 115                 if (port != 0)
 116                         setsockopt(conn->fddata,0,IPNVDE_SO_PORT,&port,sizeof(port));
 117                 snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s", sockname);
 118                 if (connect(conn->fddata, (struct sockaddr *) &sockun, sizeof(sockun)) == 0) {
 119                         snprintf(req.description,MAXDESCR,"%s user=%s PID=%d %s",
 120                                         descr,(callerpwd != NULL)?callerpwd->pw_name:"??",
 121                                         pid,getenv("SSH_CLIENT")?getenv("SSH_CLIENT"):"");
 122                         setsockopt(conn->fddata,0,IPNVDE_SO_DESCR,req.description,
 123                                         strlen(req.description+1));
 124                         *(conn->inpath.sun_path)=0; /*null string, do not delete "return path"*/
 125                         conn->fdctl=-1;
 126                         return conn;
 127                 }
 128         }
 129 #endif
 130         if((conn->fdctl = socket(AF_UNIX, SOCK_STREAM, 0)) < 0){
 131                 int err=errno;
 132                 free(conn);
 133                 errno=err;
 134                 return NULL;
 135         }
 136         if((conn->fddata = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0){
 137                 int err=errno;
 138                 close(conn->fdctl);
 139                 free(conn);
 140                 errno=err;
 141                 return NULL;
 142         }
 143         sockun.sun_family = AF_UNIX;
 144         snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s/ctl", sockname);
 145         if(connect(conn->fdctl, (struct sockaddr *) &sockun, sizeof(sockun))){
 146                 if (!strcmp(sockname, VDESTDSOCK)) {
 147                         sockname=VDETMPSOCK;
 148                         snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s/ctl", sockname);
 149                         if(connect(conn->fdctl, (struct sockaddr *) &sockun, sizeof(sockun))){
 150                                 snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s", sockname);
 151                                 if(connect(conn->fdctl, (struct sockaddr *) &sockun, sizeof(sockun))){
 152                                         close(conn->fddata);
 153                                         close(conn->fdctl);
 154                                         free(conn);
 155                                         errno=ENOENT;
 156                                         return NULL;
 157                                 }
 158                         }
 159                 }
 160         }
 161
 162         req.magic=SWITCH_MAGIC;
 163         req.version=3;
 164         req.type=REQ_NEW_CONTROL+(port << 8);
 165         req.sock.sun_family=AF_UNIX;
 166
 167         /* First choice, store the return socket from the switch in the control dir*/
 168         memset(req.sock.sun_path, 0, sizeof(req.sock.sun_path));
 169         do
 170         {
 171                 sprintf(req.sock.sun_path, "%s.%05d-%05d", sockname, pid, sockno++);
 172                 res=bind(conn->fddata, (struct sockaddr *) &req.sock, sizeof (req.sock));
 173         }
 174         while (res < 0 && errno == EADDRINUSE);
 175         if (res < 0){
 176                 /* if it is not possible -> /tmp */
 177                 memset(req.sock.sun_path, 0, sizeof(req.sock.sun_path));
 178                 do
 179                 {
 180                         sprintf(req.sock.sun_path, "/tmp/vde.%05d-%05d", pid, sockno++);
 181                         res=bind(conn->fddata, (struct sockaddr *) &req.sock, sizeof (req.sock));
 182                 }
 183                 while (res < 0 && errno == EADDRINUSE);
 184
 185                 if (res < 0){
 186                         int err=errno;
 187                         close(conn->fddata);
 188                         close(conn->fdctl);
 189                         free(conn);
 190                         errno=err;
 191                         return NULL;
 192                 }
 193         }
 194
 195         memcpy(&(conn->inpath),&req.sock,sizeof(req.sock));
 196         if (group) {
 197                 struct group *gs;
 198                 gid_t gid;
 199                 if ((gs=getgrnam(group)) == NULL)
 200                         gid=atoi(group);
 201                 else
 202                         gid=gs->gr_gid;
 203                 chown(conn->inpath.sun_path,-1,gid);
 204         }
 205         chmod(conn->inpath.sun_path,mode);
 206
 207         snprintf(req.description,MAXDESCR,"%s user=%s PID=%d %s SOCK=%s",
 208                         descr,(callerpwd != NULL)?callerpwd->pw_name:"??",
 209                         pid,getenv("SSH_CLIENT")?getenv("SSH_CLIENT"):"",req.sock.sun_path);
 210
 211         if (send(conn->fdctl,&req,sizeof(req)-MAXDESCR+strlen(req.description),0) < 0) {
 212                 int err=errno;
 213                 close(conn->fddata);
 214                 close(conn->fdctl);
 215                 free(conn);
 216                 errno=err;
 217                 return NULL;
 218         }
 219
 220         if (recv(conn->fdctl,&(dataout),sizeof(struct sockaddr_un),0)<0) {
 221                 int err=errno;
 222                 close(conn->fddata);
 223                 close(conn->fdctl);
 224                 free(conn);
 225                 errno=err;
 226                 return NULL;
 227         }
 228
 229         if (connect(conn->fddata,(struct sockaddr *)&(dataout),sizeof(struct sockaddr_un))<0) {
 230                 int err=errno;
 231                 close(conn->fddata);
 232                 close(conn->fdctl);
 233                 free(conn);
 234                 errno=err;
 235                 return NULL;
 236         }
 237         chmod(dataout.sun_path,mode);
 238
 239         return conn;
 240 }
 241
 242 ssize_t vde_recv(VDECONN *conn,void *buf,size_t len,int flags)
 243 {
 244         if (__builtin_expect(conn!=0,1))
 245                 return recv(conn->fddata,buf,len,0);
 246         else {
 247                 errno=EBADF;
 248                 return -1;
 249         }
 250 }
 251
 252 ssize_t vde_send(VDECONN *conn,const void *buf,size_t len,int flags)
 253 {
 254         if (__builtin_expect(conn!=0,1))
 255                 return send(conn->fddata,buf,len,0);
 256         else {
 257                 errno=EBADF;
 258                 return -1;
 259         }
 260 }
 261
 262 int vde_datafd(VDECONN *conn)
 263 {
 264         if (__builtin_expect(conn!=0,1))
 265                 return conn->fddata;
 266         else {
 267                 errno=EBADF;
 268                 return -1;
 269         }
 270 }
 271
 272 int vde_ctlfd(VDECONN *conn)
 273 {
 274         if (__builtin_expect(conn!=0,1))
 275                 return conn->fdctl;
 276         else {
 277                 errno=EBADF;
 278                 return -1;
 279         }
 280 }
 281
 282 int vde_close(VDECONN *conn)
 283 {
 284         if (__builtin_expect(conn!=0,1)) {
 285                 if (*(conn->inpath.sun_path))
 286                         unlink(conn->inpath.sun_path);
 287                 close(conn->fddata);
 288                 close(conn->fdctl);
 289                 free(conn);
 290                 return 0;
 291         } else {
 292                 errno=EBADF;
 293                 return -1;
 294         }
 295 }