X-Git-Url: http://git.onelab.eu/?p=distributedratelimiting.git;a=blobdiff_plain;f=libipulog%2Flibipulog.c;fp=libipulog%2Flibipulog.c;h=6adf857270815cb0761c297ac65035093060531e;hp=0000000000000000000000000000000000000000;hb=0be9704d6b24d09ebd55beedec52758cb88c570b;hpb=6747e89080a8265aa73320bd9f40a0fa6e1c161e diff --git a/libipulog/libipulog.c b/libipulog/libipulog.c new file mode 100644 index 0000000..6adf857 --- /dev/null +++ b/libipulog/libipulog.c @@ -0,0 +1,276 @@ +/* + * libipulog.c, $Revision: 5371 $ + * + * netfilter ULOG userspace library. + * + * (C) 2000-2001 by Harald Welte + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * This library is still under development, so be aware of sudden interface + * changes + * + * $Id: libipulog.c 5371 2005-05-04 01:22:18Z laforge $ + */ + +#include +#include +#include +#include +#include +#include +#if HAVE_LIBPROPER +#include +#endif + +struct ipulog_handle +{ + int fd; + u_int8_t blocking; + struct sockaddr_nl local; + struct sockaddr_nl peer; + struct nlmsghdr* last_nlhdr; +}; + +/* internal */ + + +int ipulog_errno = IPULOG_ERR_NONE; + +struct ipulog_errmap_t +{ + int errcode; + char *message; +} ipulog_errmap[] = +{ + { IPULOG_ERR_NONE, "No error" }, + { IPULOG_ERR_IMPL, "Not implemented yet" }, + { IPULOG_ERR_HANDLE, "Unable to create netlink handle" }, + { IPULOG_ERR_SOCKET, "Unable to create netlink socket" }, + { IPULOG_ERR_BIND, "Unable to bind netlink socket" }, + { IPULOG_ERR_RECVBUF, "Receive buffer size invalid" }, + { IPULOG_ERR_RECV, "Error during netlink receive" }, + { IPULOG_ERR_NLEOF, "Received EOF on netlink socket" }, + { IPULOG_ERR_TRUNC, "Receive message truncated" }, + { IPULOG_ERR_INVGR, "Invalid group specified" }, + { IPULOG_ERR_INVNL, "Invalid netlink message" }, +}; + +static ssize_t +ipulog_netlink_recvfrom(const struct ipulog_handle *h, + unsigned char *buf, size_t len) +{ + socklen_t addrlen; + int status; + struct nlmsghdr *nlh; + + if (len < sizeof(struct nlmsgerr)) { + ipulog_errno = IPULOG_ERR_RECVBUF; + return -1; + } + addrlen = sizeof(h->peer); + status = recvfrom(h->fd, buf, len, 0, (struct sockaddr *)&h->peer, + &addrlen); + if (status < 0) { + ipulog_errno = IPULOG_ERR_RECV; + return status; + } + if (addrlen != sizeof (h->peer)) { + ipulog_errno = IPULOG_ERR_RECV; + return -1; + } + if (h->peer.nl_pid != 0) { + ipulog_errno = IPULOG_ERR_RECV; + return -1; + } + if (status == 0) { + ipulog_errno = IPULOG_ERR_NLEOF; + return -1; + } + nlh = (struct nlmsghdr *)buf; + if (nlh->nlmsg_flags & MSG_TRUNC || status > len) { + ipulog_errno = IPULOG_ERR_TRUNC; + return -1; + } + return status; +} + +/* public */ + +char *ipulog_strerror(int errcode) +{ + if (errcode < 0 || errcode > IPULOG_MAXERR) + errcode = IPULOG_ERR_IMPL; + return ipulog_errmap[errcode].message; +} + +/* convert a netlink group (1-32) to a group_mask suitable for create_handle */ +u_int32_t ipulog_group2gmask(u_int32_t group) +{ + if (group < 1 || group > 32) + { + ipulog_errno = IPULOG_ERR_INVGR; + return 0; + } + return (1 << (group - 1)); +} + +/* create a ipulog handle for the reception of packets sent to gmask */ +struct ipulog_handle *ipulog_create_handle(u_int32_t gmask, + u_int32_t rcvbufsize) +{ + struct ipulog_handle *h; + int status; + + h = (struct ipulog_handle *) malloc(sizeof(struct ipulog_handle)); + if (h == NULL) + { + ipulog_errno = IPULOG_ERR_HANDLE; + return NULL; + } + memset(h, 0, sizeof(struct ipulog_handle)); +#if HAVE_LIBPROPER + /* Create and bind privileged netlink socket through Proper */ + memset(&h->local, 0, sizeof(struct sockaddr_nl)); + h->local.nl_family = AF_NETLINK; + h->local.nl_pid = getpid(); + h->local.nl_groups = gmask; + h->fd = prop_create_socket(PF_NETLINK, SOCK_RAW, NETLINK_NFLOG, + (struct sockaddr *)&h->local, sizeof(h->local)); + if (h->fd < 0) + { + ipulog_errno = IPULOG_ERR_SOCKET; + close(h->fd); + free(h); + return NULL; + } +#else + h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_NFLOG); + if (h->fd == -1) + { + ipulog_errno = IPULOG_ERR_SOCKET; + close(h->fd); + free(h); + return NULL; + } + memset(&h->local, 0, sizeof(struct sockaddr_nl)); + h->local.nl_family = AF_NETLINK; + h->local.nl_pid = getpid(); + h->local.nl_groups = gmask; + status = bind(h->fd, (struct sockaddr *)&h->local, sizeof(h->local)); + if (status == -1) + { + ipulog_errno = IPULOG_ERR_BIND; + close(h->fd); + free(h); + return NULL; + } +#endif + memset(&h->peer, 0, sizeof(struct sockaddr_nl)); + h->peer.nl_family = AF_NETLINK; + h->peer.nl_pid = 0; + h->peer.nl_groups = gmask; + + status = setsockopt(h->fd, SOL_SOCKET, SO_RCVBUF, &rcvbufsize, + sizeof(rcvbufsize)); + if (status == -1) + { + ipulog_errno = IPULOG_ERR_RECVBUF; + close(h->fd); + free(h); + return NULL; + } + + return h; +} + +/* destroy a ipulog handle */ +void ipulog_destroy_handle(struct ipulog_handle *h) +{ + close(h->fd); + free(h); +} + +#if 0 +int ipulog_set_mode() +{ +} +#endif + +/* do a BLOCKING read on an ipulog handle */ +ssize_t ipulog_read(struct ipulog_handle *h, unsigned char *buf, + size_t len, int timeout) +{ + return ipulog_netlink_recvfrom(h, buf, len); +} + +/* get a pointer to the actual start of the ipulog packet, + use this to strip netlink header */ +ulog_packet_msg_t *ipulog_get_packet(struct ipulog_handle *h, + const unsigned char *buf, + size_t len) +{ + struct nlmsghdr *nlh; + size_t remain_len; + + /* if last header in handle not inside this buffer, + * drop reference to last header */ + if ((unsigned char *)h->last_nlhdr > (buf + len) || + (unsigned char *)h->last_nlhdr < buf) { + h->last_nlhdr = NULL; + } + + if (!h->last_nlhdr) { + /* fist message in buffer */ + nlh = (struct nlmsghdr *) buf; + if (!NLMSG_OK(nlh, len)) { + /* ERROR */ + ipulog_errno = IPULOG_ERR_INVNL; + return NULL; + } + } else { + /* we are in n-th part of multilink message */ + if (h->last_nlhdr->nlmsg_type == NLMSG_DONE || + !(h->last_nlhdr->nlmsg_flags & NLM_F_MULTI)) { + /* if last part in multilink message, + * or no multipart message at all: return */ + h->last_nlhdr = NULL; + return NULL; + } + + /* calculate remaining lenght from lasthdr to end of buffer */ + remain_len = (len - + ((unsigned char *)h->last_nlhdr - buf)); + nlh = NLMSG_NEXT(h->last_nlhdr, remain_len); + } + + h->last_nlhdr = nlh; + + return NLMSG_DATA(nlh); +} + +/* print a human readable description of the last error to stderr */ +void ipulog_perror(const char *s) +{ + if (s) + fputs(s, stderr); + else + fputs("ERROR", stderr); + if (ipulog_errno) + fprintf(stderr, ": %s", ipulog_strerror(ipulog_errno)); + if (errno) + fprintf(stderr, ": %s", strerror(errno)); + fputc('\n', stderr); +} +