From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [iproute2 patch]: Add 'ip tuntap' facility for managing tun/tap devices Date: Wed, 27 May 2009 21:58:23 -0700 Message-ID: <20090527215823.343abbbe@nehalam> References: <1241433136.6126.70.camel@macbook.infradead.org> <1241433778.6126.90.camel@macbook.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: stephen.hemminger@vyatta.com, netdev@vger.kernel.org To: David Woodhouse Return-path: Received: from mail.vyatta.com ([76.74.103.46]:36335 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751497AbZE1E62 (ORCPT ); Thu, 28 May 2009 00:58:28 -0400 In-Reply-To: <1241433778.6126.90.camel@macbook.infradead.org> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 04 May 2009 11:42:58 +0100 David Woodhouse wrote: > This patch provides support for 'ip tuntap', allowing creation and > deletion of persistent tun/tap devices. > > The support for _listing_ devices relies on the patch I just sent to > netdev (<1241433136.6126.70.camel@macbook.infradead.org>), although > creation and deletion work without that patch. > > diff --git a/ip/Makefile b/ip/Makefile > index 98ba876..e868f3e 100644 > --- a/ip/Makefile > +++ b/ip/Makefile > @@ -1,6 +1,6 @@ > IPOBJ=ip.o ipaddress.o ipaddrlabel.o iproute.o iprule.o \ > rtm_map.o iptunnel.o ip6tunnel.o tunnel.o ipneigh.o ipntable.o iplink.o \ > - ipmaddr.o ipmonitor.o ipmroute.o ipprefix.o \ > + ipmaddr.o ipmonitor.o ipmroute.o ipprefix.o iptuntap.o \ > ipxfrm.o xfrm_state.o xfrm_policy.o xfrm_monitor.o \ > iplink_vlan.o link_veth.o link_gre.o > > diff --git a/ip/ip.c b/ip/ip.c > index 2bd54b2..d846a76 100644 > --- a/ip/ip.c > +++ b/ip/ip.c > @@ -47,7 +47,7 @@ static void usage(void) > "Usage: ip [ OPTIONS ] OBJECT { COMMAND | help }\n" > " ip [ -force ] -batch filename\n" > "where OBJECT := { link | addr | addrlabel | route | rule | neigh | ntable |\n" > -" tunnel | maddr | mroute | monitor | xfrm }\n" > +" tunnel | tuntap | maddr | mroute | monitor | xfrm }\n" > " OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] | -r[esolve] |\n" > " -f[amily] { inet | inet6 | ipx | dnet | link } |\n" > " -o[neline] | -t[imestamp] | -b[atch] [filename] }\n"); > @@ -75,6 +75,8 @@ static const struct cmd { > { "link", do_iplink }, > { "tunnel", do_iptunnel }, > { "tunl", do_iptunnel }, > + { "tuntap", do_iptuntap }, > + { "tap", do_iptuntap }, > { "monitor", do_ipmonitor }, > { "xfrm", do_xfrm }, > { "mroute", do_multiroute }, > diff --git a/ip/ip_common.h b/ip/ip_common.h > index 273065f..c857667 100644 > --- a/ip/ip_common.h > +++ b/ip/ip_common.h > @@ -32,6 +32,7 @@ extern int do_ipneigh(int argc, char **argv); > extern int do_ipntable(int argc, char **argv); > extern int do_iptunnel(int argc, char **argv); > extern int do_ip6tunnel(int argc, char **argv); > +extern int do_iptuntap(int argc, char **argv); > extern int do_iplink(int argc, char **argv); > extern int do_ipmonitor(int argc, char **argv); > extern int do_multiaddr(int argc, char **argv); > diff --git a/ip/iptuntap.c b/ip/iptuntap.c > new file mode 100644 > index 0000000..b480296 > --- /dev/null > +++ b/ip/iptuntap.c > @@ -0,0 +1,322 @@ > +/* > + * iptunnel.c "ip tuntap" > + * > + * 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 > + * 2 of the License, or (at your option) any later version. > + * > + * Authors: David Woodhouse > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "rt_names.h" > +#include "utils.h" > +#include "ip_common.h" > + > +#define TUNDEV "/dev/net/tun" I know this is historical legacy, but how does this play with network namespaces? > + > +static void usage(void) __attribute__((noreturn)); > + > +static void usage(void) > +{ > + fprintf(stderr, "Usage: ip tuntap { add | del } [ dev PHYS_DEV ] \n"); > + fprintf(stderr, " [ mode { tun | tap } ] [ user USER ] [ group GROUP ]\n"); > + fprintf(stderr, " [ one_queue ] [ no_pi ] [ vnet_hdr ]\n"); > + fprintf(stderr, "\n"); > + fprintf(stderr, "Where: USER := { STRING | NUMBER }\n"); > + fprintf(stderr, " GROUP := { STRING | NUMBER }\n"); > + exit(-1); > +} > + > +static int tap_add_ioctl(struct ifreq *ifr, uid_t uid, gid_t gid) > +{ > + int fd = open(TUNDEV, O_RDWR); > + int ret = -1; > + > +#ifndef IFF_TUN_EXCL > +#define IFF_TUN_EXCL 0x8000 > +#endif This shouldn't be here. It should be defined in include/linux/if_tun.h in kernel source and then a kernel sanitized version of if_tun.h should be put in iproute2 source for backwards compatibility. But why bother it doesn't seem to be defined or used by current kernel?? > + ifr->ifr_flags |= IFF_TUN_EXCL; Would prefer open() next to the test. > + if (fd < 0) { > + perror("open"); > + return -1; > + } > + if (ioctl(fd, TUNSETIFF, ifr)) { > + perror("ioctl(TUNSETIFF)"); > + goto out; > + } > + if (uid != -1 && ioctl(fd, TUNSETOWNER, uid)) { > + perror("ioctl(TUNSETOWNER)"); > + goto out; > + } > + if (gid != -1 && ioctl(fd, TUNSETGROUP, gid)) { > + perror("ioctl(TUNSETGROUP)"); > + goto out; > + } > + if (ioctl(fd, TUNSETPERSIST, 1)) { > + perror("ioctl(TUNSETPERSIST)"); > + goto out; > + } > + ret = 0; > + out: > + close(fd); > + return ret; > +} > + > +static int tap_del_ioctl(struct ifreq *ifr) > +{ > + int fd = open(TUNDEV, O_RDWR); > + int ret = -1; > + > + if (fd < 0) { > + perror("open"); > + return -1; > + } > + if (ioctl(fd, TUNSETIFF, ifr)) { > + perror("ioctl(TUNSETIFF)"); > + goto out; > + } > + if (ioctl(fd, TUNSETPERSIST, 0)) { > + perror("ioctl(TUNSETPERSIST)"); > + goto out; > + } > + ret = 0; > + out: > + close(fd); > + return ret; > + > +} > +static int parse_args(int argc, char **argv, struct ifreq *ifr, uid_t *uid, gid_t *gid) > +{ > + int count = 0; > + > + memset(ifr, 0, sizeof(*ifr)); > + > + ifr->ifr_flags |= IFF_NO_PI; > + > + while (argc > 0) { > + if (strcmp(*argv, "mode") == 0) { The argument parsing in ip commands uses matches() rather than strcmp to allow for partial completion. > + NEXT_ARG(); > + if (strcmp(*argv, "tun") == 0) { > + if (ifr->ifr_flags & IFF_TAP) { > + fprintf(stderr,"You managed to ask for more than one tunnel mode.\n"); > + exit(-1); > + } > + ifr->ifr_flags |= IFF_TUN; > + } else if (strcmp(*argv, "tap") == 0) { > + if (ifr->ifr_flags & IFF_TUN) { > + fprintf(stderr,"You managed to ask for more than one tunnel mode.\n"); > + exit(-1); > + } > + ifr->ifr_flags |= IFF_TAP; > + } else { > + fprintf(stderr,"Cannot guess tunnel mode.\n"); > + exit(-1); > + } > + } else if (uid && strcmp(*argv, "user") == 0) { > + char *end; > + unsigned long user; > + > + NEXT_ARG(); > + if (**argv && ((user = strtol(*argv, &end, 10)), !*end)) > + *uid = user; > + else { > + struct passwd *pw = getpwnam(*argv); > + if (!pw) { > + fprintf(stderr, "invalid user \"%s\"\n", *argv); > + exit(-1); > + } > + *uid = pw->pw_uid; > + } > + } else if (gid && strcmp(*argv, "group") == 0) { > + char *end; > + unsigned long group; > + > + NEXT_ARG(); > + > + if (**argv && ((group = strtol(*argv, &end, 10)), !*end)) > + *gid = group; > + else { > + struct group *gr = getgrnam(*argv); > + if (!gr) { > + fprintf(stderr, "invalid group \"%s\"\n", *argv); > + exit(-1); > + } > + *gid = gr->gr_gid; > + } > + } else if (strcmp(*argv, "pi") == 0) { > + ifr->ifr_flags &= ~IFF_NO_PI; > + } else if (strcmp(*argv, "one_queue") == 0) { > + ifr->ifr_flags |= IFF_ONE_QUEUE; > + } else if (strcmp(*argv, "vnet_hdr") == 0) { > + ifr->ifr_flags |= IFF_VNET_HDR; > + } else if (strcmp(*argv, "dev") == 0) { > + NEXT_ARG(); > + strncpy(ifr->ifr_name, *argv, IFNAMSIZ-1); > + } else { > + if (strcmp(*argv, "name") == 0) { > + NEXT_ARG(); > + } else if (matches(*argv, "help") == 0) > + usage(); > + if (ifr->ifr_name[0]) > + duparg2("name", *argv); > + strncpy(ifr->ifr_name, *argv, IFNAMSIZ); > + } > + count++; > + argc--; argv++; > + } > + > + return 0; > +} > + > + > +static int do_add(int argc, char **argv) > +{ > + struct ifreq ifr; > + uid_t uid = -1; > + gid_t gid = -1; > + > + if (parse_args(argc, argv, &ifr, &uid, &gid) < 0) > + return -1; > + > + if (!(ifr.ifr_flags & TUN_TYPE_MASK)) { > + fprintf(stderr, "You failed to specify a tunnel mode\n"); > + return -1; > + } > + return tap_add_ioctl(&ifr, uid, gid); > +} > + > +static int do_del(int argc, char **argv) > +{ > + struct ifreq ifr; > + > + if (parse_args(argc, argv, &ifr, NULL, NULL) < 0) > + return -1; > + > + return tap_del_ioctl(&ifr); > +} > + > +static int read_prop(char *dev, char *prop, long *value) > +{ > + char fname[IFNAMSIZ+25], buf[80], *endp; > + ssize_t len; > + int fd; > + long result; > + > + sprintf(fname, "/sys/class/net/%s/%s", dev, prop); > + fd = open(fname, O_RDONLY); > + if (fd < 0) { > + if (strcmp(prop, "tun_flags")) > + fprintf(stderr, "open %s: %s\n", fname, strerror(errno)); > + return -1; > + } > + len = read(fd, buf, sizeof(buf)-1); > + close(fd); > + if (len < 0) { > + fprintf(stderr, "read %s: %s", fname, strerror(errno)); > + return -1; > + } > + > + buf[len] = 0; > + result = strtol(buf, &endp, 0); > + if (*endp != '\n') { > + fprintf(stderr, "Failed to parse %s\n", fname); > + return -1; > + } > + *value = result; > + return 0; > +} > + > +static void print_flags(long flags) > +{ > + if (flags & IFF_TUN) > + printf(" tun"); > + > + if (flags & IFF_TAP) > + printf(" tap"); > + > + if (!(flags & IFF_NO_PI)) > + printf(" pi"); > + > + if (flags & IFF_ONE_QUEUE) > + printf(" one_queue"); > + > + if (flags & IFF_VNET_HDR) > + printf(" vnet_hdr"); > + > + flags &= ~(IFF_TUN|IFF_TAP|IFF_NO_PI|IFF_ONE_QUEUE|IFF_VNET_HDR); > + if (flags) > + printf(" UNKNOWN_FLAGS:%x", flags); > +} > + > +static int do_show(int argc, char **argv) > +{ > + DIR *dir; > + struct dirent *d; > + long flags, owner = -1, group = -1; > + int i; > + > + dir = opendir("/sys/class/net"); > + if (!dir) { > + perror("opendir"); > + return -1; > + } > + while ((d = readdir(dir))) { > + if (d->d_name[0] == '.' && > + (d->d_name[1] == 0 || d->d_name[1] == '.')) > + continue; > + > + if (read_prop(d->d_name, "tun_flags", &flags)) > + continue; > + > + read_prop(d->d_name, "owner", &owner); > + read_prop(d->d_name, "group", &group); > + > + printf("%s:", d->d_name); > + print_flags(flags); > + if (owner != -1) > + printf(" user %ld", owner); > + if (group != -1) > + printf(" group %ld", group); > + printf("\n"); > + } > + return 0; > +} > + > +int do_iptuntap(int argc, char **argv) > +{ > + if (argc > 0) { > + if (matches(*argv, "add") == 0) > + return do_add(argc-1, argv+1); > + if (matches(*argv, "del") == 0) > + return do_del(argc-1, argv+1); > + if (matches(*argv, "show") == 0 || > + matches(*argv, "lst") == 0 || > + matches(*argv, "list") == 0) > + return do_show(argc-1, argv+1); > + if (matches(*argv, "help") == 0) > + usage(); > + } else > + return do_show(0, NULL); > + > + fprintf(stderr, "Command \"%s\" is unknown, try \"ip tuntap help\".\n", *argv); > + exit(-1); > +} > --