/* * netsniff-ng - the packet sniffing beast * Copyright 2012 Daniel Borkmann. * Subject to the GPL, version 2. * Parts derived from iw, subject to ISC license. * Copyright 2007, 2008 Johannes Berg * Copyright 2007 Andy Lutomirski * Copyright 2007 Mike Kershaw * Copyright 2008-2009 Luis R. Rodriguez */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include "die.h" #include "str.h" #include "dev.h" #include "mac80211.h" #include "xmalloc.h" #include "built_in.h" struct nl80211_state { struct nl_sock *nl_sock; struct nl_cache *nl_cache; struct genl_family *nl80211; }; static void get_mac80211_phydev(const char *device, char *phydev_path, size_t phydev_len) { int ret; char *pathstr; ssize_t num; ret = asprintf(&pathstr, "/sys/class/net/%s/phy80211", device); if (ret < 0) panic("Can't generate path name string for /sys/class/net device"); num = readlink(pathstr, phydev_path, phydev_len); if (num < 0) { if (errno == ENOENT || errno == EINVAL) panic("It's probably not a mac80211 device!\n"); panic("Can't readlink %s: %s!\n", pathstr, strerror(errno)); } xfree(pathstr); phydev_path[min_t(size_t, num, phydev_len - 1)] = 0; } static inline struct nl_msg *nl80211_nlmsg_xalloc(void) { struct nl_msg *ret = nlmsg_alloc(); if (!ret) panic("Cannot allocate nlmsg memory!\n"); return ret; } static inline struct nl_sock *nl80211_nl_socket_xalloc(void) { struct nl_sock *ret = nl_socket_alloc(); if (!ret) panic("Cannot allocate nl socket memory!\n"); return ret; } static void nl80211_init(struct nl80211_state *state) { int ret; state->nl_sock = nl80211_nl_socket_xalloc(); ret = genl_connect(state->nl_sock); if (ret) panic("Cannot connect generic netlink!\n"); ret = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache); if (ret < 0) panic("Failed to allocate generic netlink cache: %s!", nl_geterror(-ret)); state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211"); if (!state->nl80211) panic("nl80211 not found in netlink cache!\n"); } static void nl80211_cleanup(struct nl80211_state *state) { genl_family_put(state->nl80211); nl_cache_free(state->nl_cache); nl_socket_free(state->nl_sock); } static int nl80211_wait_handler(struct nl_msg *msg __maybe_unused, void *arg) { int *finished = arg; *finished = 1; return NL_STOP; } static int nl80211_error_handler(struct sockaddr_nl *nla __maybe_unused, struct nlmsgerr *err, void *arg __maybe_unused) { panic("nl80211 returned with error %d\n", err->error); } static int nl80211_add_mon_if(struct nl80211_state *state, const char *device, const char *mondevice) { int ifindex, ret; struct nl_msg *msg; struct nl_cb *cb = NULL; int finished = 0; ifindex = device_ifindex(device); msg = nl80211_nlmsg_xalloc(); genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0, 0, NL80211_CMD_NEW_INTERFACE, 0); NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex); NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice); NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR); ret = nl_send_auto_complete(state->nl_sock, msg); if (ret < 0) { if (ret == -ENFILE) { nlmsg_free(msg); return -EBUSY; } panic("Cannot send_auto_complete!\n"); } cb = nl_cb_alloc(NL_CB_CUSTOM); if (!cb) panic("Cannot alloc nl_cb!\n"); nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, nl80211_wait_handler, &finished); nl_cb_err(cb, NL_CB_CUSTOM, nl80211_error_handler, NULL); nl_recvmsgs(state->nl_sock, cb); if (!finished) { ret = nl_wait_for_ack(state->nl_sock); if (ret < 0) { if (ret == -ENFILE) { nlmsg_free(msg); return -EBUSY; } panic("Waiting for netlink ack failed!\n"); } } nl_cb_put(cb); nlmsg_free(msg); return 0; nla_put_failure: panic("nla put failure!\n"); return -EIO; /* dummy */ } static int nl80211_del_mon_if(struct nl80211_state *state, const char *mondevice) { int ifindex, ret; struct nl_msg *msg; ifindex = device_ifindex(mondevice); msg = nl80211_nlmsg_xalloc(); genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0, 0, NL80211_CMD_DEL_INTERFACE, 0); NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex); ret = nl_send_auto_complete(state->nl_sock, msg); if (ret < 0) panic("Cannot send_auto_complete!\n"); ret = nl_wait_for_ack(state->nl_sock); if (ret < 0) panic("Waiting for netlink ack failed!\n"); nlmsg_free(msg); return 0; nla_put_failure: panic("nla put failure!\n"); return -EIO; /* dummy */ } void enter_rfmon_mac80211(const char *device, char **mondev) { int ret; short flags; uint32_t n; char phydev_path[256]; struct nl80211_state nlstate; /* XXX: is this already a monN device? */ get_mac80211_phydev(device, phydev_path, sizeof(phydev_path)); nl80211_init(&nlstate); for (n = 0; n < UINT_MAX; n++) { char mondevice[32]; slprintf(mondevice, sizeof(mondevice), "mon%u", n); ret = nl80211_add_mon_if(&nlstate, device, mondevice); if (ret == 0) { *mondev = xstrdup(mondevice); flags = device_get_flags(*mondev); flags |= IFF_UP | IFF_RUNNING; device_set_flags(*mondev, flags); nl80211_cleanup(&nlstate); return; } } panic("No free monN interfaces!\n"); } void leave_rfmon_mac80211(const char *mondev) { short flags; struct nl80211_state nlstate; flags = device_get_flags(mondev); flags &= ~(IFF_UP | IFF_RUNNING); device_set_flags(mondev, flags); nl80211_init(&nlstate); nl80211_del_mon_if(&nlstate, mondev); nl80211_cleanup(&nlstate); } ance at open-time, and not be artificially tied to one particular ptmx inode. The patch itself is actually fairly straightforward, and apart from some locking and return path cleanups it's pretty mechanical: - the interfaces that devpts exposes all take "struct pts_fs_info *" instead of "struct inode *ptmx_inode" now. NOTE! The "struct pts_fs_info" thing is a completely opaque structure as far as the pty driver is concerned: it's still declared entirely internally to devpts. So the pty code can't actually access it in any way, just pass it as a "cookie" to the devpts code. - the "look up the pts fs info" is now a single clear operation, that also does the reference count increment on the pts superblock. So "devpts_add/del_ref()" is gone, and replaced by a "lookup and get ref" operation (devpts_get_ref(inode)), along with a "put ref" op (devpts_put_ref()). - the pty master "tty->driver_data" field now contains the pts_fs_info, not the ptmx inode. - because we don't care about the ptmx inode any more as some kind of base index, the ref counting can now drop the inode games - it just gets the ref on the superblock. - the pts_fs_info now has a back-pointer to the super_block. That's so that we can easily look up the information we actually need. Although quite often, the pts fs info was actually all we wanted, and not having to look it up based on some magical inode makes things more straightforward. In particular, now that "devpts_get_ref(inode)" operation should really be the *only* place we need to look up what devpts instance we're associated with, and we do it exactly once, at ptmx_open() time. The other side of this is that one ptmx node could now be associated with multiple different devpts instances - you could have a single /dev/ptmx node, and then have multiple mount namespaces with their own instances of devpts mounted on /dev/pts/. And that's all perfectly sane in a model where we just look up the pts instance at open time. This will eventually allow us to get rid of our odd single-vs-multiple pts instance model, but this patch in itself changes no semantics, only an internal binding model. Cc: Eric Biederman <ebiederm@xmission.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Jann Horn <jann@thejh.net> Cc: Greg KH <greg@kroah.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Florian Weimer <fw@deneb.enyo.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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