Repository : ssh://git@open-mesh.org/batctl

On branch : next

commit 62127974e9994a5aceb3879a1d113a2414d07620 Author: Sven Eckelmann sven@narfation.org Date: Mon Jan 6 20:37:23 2014 +0100

batctl: Use libnl to implement mac resolver

It is not necessary to have code duplicated which is already available in libraries like libnl-3.0 or libnl-tiny. This is done to reduce maintenance and security risks.

Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Marek Lindner mareklindner@neomailbox.ch

62127974e9994a5aceb3879a1d113a2414d07620 Makefile | 18 ++++ functions.c | 312 +++++++++++++++++++++++++---------------------------------- 2 files changed, 149 insertions(+), 181 deletions(-)

diff --git a/Makefile b/Makefile index fc0925d..0eb71a1 100755 --- a/Makefile +++ b/Makefile @@ -43,6 +43,24 @@ ifndef V endif endif

+ifeq ($(origin PKG_CONFIG), undefined) + PKG_CONFIG = pkg-config + ifeq ($(shell which $(PKG_CONFIG) 2>/dev/null),) + $(error $(PKG_CONFIG) not found) + endif +endif + +ifeq ($(origin LIBNL_CFLAGS) $(origin LIBNL_LDLIBS), undefined undefined) + LIBNL_NAME ?= libnl-3.0 + ifeq ($(shell $(PKG_CONFIG) --modversion $(LIBNL_NAME) 2>/dev/null),) + $(error No $(LIBNL_NAME) development libraries found!) + endif + LIBNL_CFLAGS += $(shell $(PKG_CONFIG) --cflags $(LIBNL_NAME)) + LIBNL_LDLIBS += $(shell $(PKG_CONFIG) --libs $(LIBNL_NAME)) +endif +CFLAGS += $(LIBNL_CFLAGS) +LDLIBS += $(LIBNL_LDLIBS) + # standard build tools ifeq ($(CONFIG_BATCTL_BISECT),y) OBJ += $(OBJ_BISECT) diff --git a/functions.c b/functions.c index 10a7f86..c21431c 100644 --- a/functions.c +++ b/functions.c @@ -38,9 +38,13 @@ #include <net/ethernet.h> #include <linux/rtnetlink.h> #include <linux/neighbour.h> -#include <sys/uio.h> #include <errno.h> #include <net/if.h> +#include <netlink/socket.h> +#include <netlink/netlink.h> +#include <netlink/handlers.h> +#include <netlink/msg.h> +#include <netlink/attr.h>

#include "main.h" #include "functions.h" @@ -457,47 +461,6 @@ static int resolve_l3addr(int ai_family, const char *asc, void *l3addr) return ret; }

-static void request_mac_resolve(int ai_family, const void *l3addr) -{ - const struct sockaddr *sockaddr; - struct sockaddr_in inet4; - struct sockaddr_in6 inet6; - size_t sockaddr_len; - int sock; - char t = 0; - - sock = socket(ai_family, SOCK_DGRAM, IPPROTO_UDP); - if (sock < 0) - return; - - switch (ai_family) { - case AF_INET: - memset(&inet4, 0, sizeof(inet4)); - inet4.sin_family = ai_family; - inet4.sin_port = htons(9); - memcpy(&inet4.sin_addr.s_addr, l3addr, - sizeof(inet4.sin_addr.s_addr)); - sockaddr = (const struct sockaddr *)&inet4; - sockaddr_len = sizeof(inet4); - break; - case AF_INET6: - memset(&inet6, 0, sizeof(inet6)); - inet6.sin6_family = ai_family; - inet6.sin6_port = htons(9); - memcpy(&inet6.sin6_addr.s6_addr, l3addr, - sizeof(inet6.sin6_addr.s6_addr)); - sockaddr = (const struct sockaddr *)&inet6; - sockaddr_len = sizeof(inet6); - break; - default: - close(sock); - return; - } - - sendto(sock, &t, sizeof(t), 0, sockaddr, sockaddr_len); - close(sock); -} - /** * batadv_rtnl_open - open a socket to rtnl and send a request * @nh: the header of the request to send @@ -542,178 +505,165 @@ outclose: return ret; }

-static int resolve_mac_from_cache_open(int ai_family) +static void request_mac_resolve(int ai_family, const void *l3addr) { - struct { - struct nlmsghdr hdr; - struct ndmsg msg; - } nlreq; - - memset(&nlreq, 0, sizeof(nlreq)); - nlreq.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(nlreq.msg)); - nlreq.hdr.nlmsg_type = RTM_GETNEIGH; - nlreq.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; - nlreq.msg.ndm_family = ai_family; + const struct sockaddr *sockaddr; + struct sockaddr_in inet4; + struct sockaddr_in6 inet6; + size_t sockaddr_len; + int sock; + char t = 0;

- return batadv_rtnl_open(&nlreq, NETLINK_ROUTE); -} + sock = socket(ai_family, SOCK_DGRAM, IPPROTO_UDP); + if (sock < 0) + return;

-static ssize_t resolve_mac_from_cache_dump(int sock, void **buf, size_t *buflen) -{ - struct iovec iov; - struct msghdr msg; - ssize_t ret = -1; - int flags = MSG_PEEK | MSG_TRUNC; + switch (ai_family) { + case AF_INET: + memset(&inet4, 0, sizeof(inet4)); + inet4.sin_family = ai_family; + inet4.sin_port = htons(9); + memcpy(&inet4.sin_addr.s_addr, l3addr, + sizeof(inet4.sin_addr.s_addr)); + sockaddr = (const struct sockaddr *)&inet4; + sockaddr_len = sizeof(inet4); + break; + case AF_INET6: + memset(&inet6, 0, sizeof(inet6)); + inet6.sin6_family = ai_family; + inet6.sin6_port = htons(9); + memcpy(&inet6.sin6_addr.s6_addr, l3addr, + sizeof(inet6.sin6_addr.s6_addr)); + sockaddr = (const struct sockaddr *)&inet6; + sockaddr_len = sizeof(inet6); + break; + default: + close(sock); + return; + }

- memset(&msg, 0, sizeof(msg)); - memset(&iov, 0, sizeof(iov)); + sendto(sock, &t, sizeof(t), 0, sockaddr, sockaddr_len); + close(sock); +}

- msg.msg_iov = &iov; - msg.msg_iovlen = 1; - msg.msg_controllen = 0; - msg.msg_control = NULL; - msg.msg_flags = 0; +struct resolve_mac_nl_arg { + int ai_family; + const void *l3addr; + struct ether_addr *mac_result; + int found; +};

- iov.iov_len = *buflen; - iov.iov_base = *buf; +static struct nla_policy neigh_policy[NDA_MAX+1] = { + [NDA_CACHEINFO] = { .minlen = sizeof(struct nda_cacheinfo) }, + [NDA_PROBES] = { .type = NLA_U32 }, +};

- ret = recvmsg(sock, &msg, flags); +static int resolve_mac_from_parse(struct nl_msg *msg, void *arg) +{ + struct nlattr *tb[NDA_MAX + 1]; + struct ndmsg *nm; + int ret; + int l3_len; + struct resolve_mac_nl_arg *nl_arg = arg; + uint8_t *mac; + uint8_t *l3addr; + + nm = nlmsg_data(nlmsg_hdr(msg)); + ret = nlmsg_parse(nlmsg_hdr(msg), sizeof(*nm), tb, NDA_MAX, + neigh_policy); if (ret < 0) goto err;

- if (msg.msg_flags & MSG_TRUNC) { - if ((size_t)ret <= *buflen) { - ret = -ENOBUFS; - goto err; - } - - while (*buflen <= (size_t)ret) { - if (*buflen == 0) - *buflen = 1; - *buflen *= 2; - } + if (nl_arg->ai_family != nm->ndm_family) + goto err;

- *buf = realloc(*buf, *buflen); - if (!*buf) { - ret = -ENOMEM; - *buflen = 0; - goto err; - } + switch (nl_arg->ai_family) { + case AF_INET: + l3_len = 4; + break; + case AF_INET6: + l3_len = 16; + break; + default: + l3_len = 0; } - flags = 0;

- ret = recvmsg(sock, &msg, flags); - if (ret < 0) + if (l3_len == 0) goto err;

- return ret; -err: - free(*buf); - *buf = NULL; - return ret; -} + if (!tb[NDA_LLADDR] || !tb[NDA_DST]) + goto err;

-static int resolve_mac_from_cache_parse(struct ndmsg *ndmsg, size_t len_payload, - struct ether_addr *mac_addr, - uint8_t *l3addr, - size_t l3_len) -{ - int l3found, llfound; - struct rtattr *rtattr; - struct ether_addr mac_empty; - - l3found = 0; - llfound = 0; - memset(&mac_empty, 0, sizeof(mac_empty)); - - for (rtattr = RTM_RTA(ndmsg); RTA_OK(rtattr, len_payload); - rtattr = RTA_NEXT(rtattr, len_payload)) { - switch (rtattr->rta_type) { - case NDA_DST: - memcpy(l3addr, RTA_DATA(rtattr), l3_len); - l3found = 1; - break; - case NDA_LLADDR: - memcpy(mac_addr, RTA_DATA(rtattr), ETH_ALEN); - if (memcmp(mac_addr, &mac_empty, - sizeof(mac_empty)) == 0) - llfound = 0; - else - llfound = 1; - break; - } + if (nla_len(tb[NDA_LLADDR]) != ETH_ALEN) + goto err; + + if (nla_len(tb[NDA_DST]) != l3_len) + goto err; + + mac = nla_data(tb[NDA_LLADDR]); + l3addr = nla_data(tb[NDA_DST]); + + if (memcmp(nl_arg->l3addr, l3addr, l3_len) == 0) { + memcpy(nl_arg->mac_result, mac, ETH_ALEN); + nl_arg->found = 1; }

- return l3found && llfound; +err: + if (nl_arg->found) + return NL_STOP; + else + return NL_OK; }

static struct ether_addr *resolve_mac_from_cache(int ai_family, const void *l3addr) { - uint8_t l3addr_tmp[16]; - static struct ether_addr mac_tmp; + struct nl_sock *sock; struct ether_addr *mac_result = NULL; - void *buf = NULL; - size_t buflen; - struct nlmsghdr *nh; - ssize_t len; - size_t l3_len, mlen; - int socknl; - int parsed; - int finished = 0; - - switch (ai_family) { - case AF_INET: - l3_len = 4; - break; - case AF_INET6: - l3_len = 16; - break; - default: - l3_len = 0; - } - - buflen = 8192; - buf = malloc(buflen); - if (!buf) + static struct ether_addr mac_tmp; + int ret; + struct rtgenmsg gmsg = { + .rtgen_family = ai_family, + }; + struct nl_cb *cb = NULL; + struct resolve_mac_nl_arg arg = { + .ai_family = ai_family, + .l3addr = l3addr, + .mac_result = &mac_tmp, + .found = 0, + }; + + sock = nl_socket_alloc(); + if (!sock) goto err;

- socknl = resolve_mac_from_cache_open(ai_family); - if (socknl < 0) + ret = nl_connect(sock, NETLINK_ROUTE); + if (ret < 0) goto err;

+ ret = nl_send_simple(sock, RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP, + &gmsg, sizeof(gmsg)); + if (ret < 0) + goto err;

- while (!finished) { - len = resolve_mac_from_cache_dump(socknl, &buf, &buflen); - if (len < 0) - goto err_sock; - mlen = len; + cb = nl_cb_alloc(NL_CB_DEFAULT); + if (!cb) + goto err;

- for (nh = buf; NLMSG_OK(nh, mlen); nh = NLMSG_NEXT(nh, mlen)) { - if (nh->nlmsg_type == NLMSG_DONE) { - finished = 1; - break; - } + nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, resolve_mac_from_parse, &arg); + ret = nl_recvmsgs(sock, cb); + if (ret < 0) + goto err;

- parsed = resolve_mac_from_cache_parse(NLMSG_DATA(nh), - RTM_PAYLOAD(nh), - &mac_tmp, - l3addr_tmp, - l3_len); - if (parsed) { - if (memcmp(&l3addr_tmp, l3addr, l3_len) == 0) { - mac_result = &mac_tmp; - finished = 1; - break; - } - } - } - } + if (arg.found) + mac_result = &mac_tmp;

-err_sock: - close(socknl); err: - free(buf); + if (cb) + nl_cb_put(cb); + if (sock) + nl_socket_free(sock); + return mac_result; }