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 #undef 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         if((conn->fdctl = socket(AF_UNIX, SOCK_STREAM, 0)) < 0){
 112                 int err=errno;
 113                 free(conn);
 114                 errno=err;
 115                 return NULL;
 116         }
 117 #ifdef USE_IPNVDE
 118         if((conn->fddata = socket(AF_IPNVDE,SOCK_RAW,IPNVDE_ANY)) >= 0) {
 119                 /* IPNVDE service exists */
 120                 sockun.sun_family = AF_IPNVDE;
 121                 if (port != 0)
 122                         setsockopt(conn->fddata,0,IPNVDE_SO_PORT,&port,sizeof(port));
 123                 snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s", sockname);
 124                 if (connect(conn->fddata, (struct sockaddr *) &sockun, sizeof(sockun)) == 0) {
 125                         snprintf(req.description,MAXDESCR,"%s user=%s PID=%d %s",
 126                                         descr,(callerpwd != NULL)?callerpwd->pw_name:"??",
 127                                         pid,getenv("SSH_CLIENT")?getenv("SSH_CLIENT"):"");
 128                         setsockopt(conn->fddata,0,IPNVDE_SO_DESCR,req.description,
 129                                         strlen(req.description+1));
 130                         *(conn->inpath.sun_path)=0; /*null string, do not delete "return path"*/
 131                         return conn;
 132                 }
 133         }
 134 #endif
 135         if((conn->fddata = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0){
 136                 int err=errno;
 137                 close(conn->fdctl);
 138                 free(conn);
 139                 errno=err;
 140                 return NULL;
 141         }
 142         sockun.sun_family = AF_UNIX;
 143         snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s/ctl", sockname);
 144         if(connect(conn->fdctl, (struct sockaddr *) &sockun, sizeof(sockun))){
 145                 if (!strcmp(sockname, VDESTDSOCK)) {
 146                         sockname=VDETMPSOCK;
 147                         snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s/ctl", sockname);
 148                         if(connect(conn->fdctl, (struct sockaddr *) &sockun, sizeof(sockun))){
 149                                 snprintf(sockun.sun_path, sizeof(sockun.sun_path), "%s", sockname);
 150                                 if(connect(conn->fdctl, (struct sockaddr *) &sockun, sizeof(sockun))){
 151                                         close(conn->fddata);
 152                                         close(conn->fdctl);
 153                                         free(conn);
 154                                         errno=ENOENT;
 155                                         return NULL;
 156                                 }
 157                         }
 158                 }
 159         }
 160
 161         req.magic=SWITCH_MAGIC;
 162         req.version=3;
 163         req.type=REQ_NEW_CONTROL+(port << 8);
 164         req.sock.sun_family=AF_UNIX;
 165
 166         /* First choice, store the return socket from the switch in the control dir*/
 167         memset(req.sock.sun_path, 0, sizeof(req.sock.sun_path));
 168         do
 169         {
 170                 sprintf(req.sock.sun_path, "%s.%05d-%05d", sockname, pid, sockno++);
 171                 res=bind(conn->fddata, (struct sockaddr *) &req.sock, sizeof (req.sock));
 172         }
 173         while (res < 0 && errno == EADDRINUSE);
 174         if (res < 0){
 175                 /* if it is not possible -> /tmp */
 176                 memset(req.sock.sun_path, 0, sizeof(req.sock.sun_path));
 177                 do
 178                 {
 179                         sprintf(req.sock.sun_path, "/tmp/vde.%05d-%05d", pid, sockno++);
 180                         res=bind(conn->fddata, (struct sockaddr *) &req.sock, sizeof (req.sock));
 181                 }
 182                 while (res < 0 && errno == EADDRINUSE);
 183
 184                 if (res < 0){
 185                         int err=errno;
 186                         close(conn->fddata);
 187                         close(conn->fdctl);
 188                         free(conn);
 189                         errno=err;
 190                         return NULL;
 191                 }
 192         }
 193
 194         memcpy(&(conn->inpath),&req.sock,sizeof(req.sock));
 195         if (group) {
 196                 struct group *gs;
 197                 gid_t gid;
 198                 if ((gs=getgrnam(group)) == NULL)
 199                         gid=atoi(group);
 200                 else
 201                         gid=gs->gr_gid;
 202                 chown(conn->inpath.sun_path,-1,gid);
 203         }
 204         chmod(conn->inpath.sun_path,mode);
 205
 206         snprintf(req.description,MAXDESCR,"%s user=%s PID=%d %s SOCK=%s",
 207                         descr,(callerpwd != NULL)?callerpwd->pw_name:"??",
 208                         pid,getenv("SSH_CLIENT")?getenv("SSH_CLIENT"):"",req.sock.sun_path);
 209
 210         if (send(conn->fdctl,&req,sizeof(req)-MAXDESCR+strlen(req.description),0) < 0) {
 211                 int err=errno;
 212                 close(conn->fddata);
 213                 close(conn->fdctl);
 214                 free(conn);
 215                 errno=err;
 216                 return NULL;
 217         }
 218
 219         if (recv(conn->fdctl,&(dataout),sizeof(struct sockaddr_un),0)<0) {
 220                 int err=errno;
 221                 close(conn->fddata);
 222                 close(conn->fdctl);
 223                 free(conn);
 224                 errno=err;
 225                 return NULL;
 226         }
 227
 228         if (connect(conn->fddata,(struct sockaddr *)&(dataout),sizeof(struct sockaddr_un))<0) {
 229                 int err=errno;
 230                 close(conn->fddata);
 231                 close(conn->fdctl);
 232                 free(conn);
 233                 errno=err;
 234                 return NULL;
 235         }
 236         chmod(dataout.sun_path,mode);
 237
 238         return conn;
 239 }
 240
 241 ssize_t vde_recv(VDECONN *conn,void *buf,size_t len,int flags)
 242 {
 243         if (__builtin_expect(conn!=0,1))
 244                 return recv(conn->fddata,buf,len,0);
 245         else {
 246                 errno=EBADF;
 247                 return -1;
 248         }
 249 }
 250
 251 ssize_t vde_send(VDECONN *conn,const void *buf,size_t len,int flags)
 252 {
 253         if (__builtin_expect(conn!=0,1))
 254                 return send(conn->fddata,buf,len,0);
 255         else {
 256                 errno=EBADF;
 257                 return -1;
 258         }
 259 }
 260
 261 int vde_datafd(VDECONN *conn)
 262 {
 263         if (__builtin_expect(conn!=0,1))
 264                 return conn->fddata;
 265         else {
 266                 errno=EBADF;
 267                 return -1;
 268         }
 269 }
 270
 271 int vde_ctlfd(VDECONN *conn)
 272 {
 273         if (__builtin_expect(conn!=0,1))
 274                 return conn->fdctl;
 275         else {
 276                 errno=EBADF;
 277                 return -1;
 278         }
 279 }
 280
 281 int vde_close(VDECONN *conn)
 282 {
 283         if (__builtin_expect(conn!=0,1)) {
 284                 if (*(conn->inpath.sun_path))
 285                         unlink(conn->inpath.sun_path);
 286                 close(conn->fddata);
 287                 close(conn->fdctl);
 288                 free(conn);
 289                 return 0;
 290         } else {
 291                 errno=EBADF;
 292                 return -1;
 293         }
 294 }