diff options
Diffstat (limited to 'package/libnl-tiny/src/nl.c')
-rw-r--r-- | package/libnl-tiny/src/nl.c | 720 |
1 files changed, 0 insertions, 720 deletions
diff --git a/package/libnl-tiny/src/nl.c b/package/libnl-tiny/src/nl.c deleted file mode 100644 index 99e9aebeb..000000000 --- a/package/libnl-tiny/src/nl.c +++ /dev/null @@ -1,720 +0,0 @@ -/* - * lib/nl.c Core Netlink Interface - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation version 2.1 - * of the License. - * - * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch> - */ - -/** - * @defgroup core Core - * - * @details - * @par 1) Connecting the socket - * @code - * // Bind and connect the socket to a protocol, NETLINK_ROUTE in this example. - * nl_connect(sk, NETLINK_ROUTE); - * @endcode - * - * @par 2) Sending data - * @code - * // The most rudimentary method is to use nl_sendto() simply pushing - * // a piece of data to the other netlink peer. This method is not - * // recommended. - * const char buf[] = { 0x01, 0x02, 0x03, 0x04 }; - * nl_sendto(sk, buf, sizeof(buf)); - * - * // A more comfortable interface is nl_send() taking a pointer to - * // a netlink message. - * struct nl_msg *msg = my_msg_builder(); - * nl_send(sk, nlmsg_hdr(msg)); - * - * // nl_sendmsg() provides additional control over the sendmsg() message - * // header in order to allow more specific addressing of multiple peers etc. - * struct msghdr hdr = { ... }; - * nl_sendmsg(sk, nlmsg_hdr(msg), &hdr); - * - * // You're probably too lazy to fill out the netlink pid, sequence number - * // and message flags all the time. nl_send_auto_complete() automatically - * // extends your message header as needed with an appropriate sequence - * // number, the netlink pid stored in the netlink socket and the message - * // flags NLM_F_REQUEST and NLM_F_ACK (if not disabled in the socket) - * nl_send_auto_complete(sk, nlmsg_hdr(msg)); - * - * // Simple protocols don't require the complex message construction interface - * // and may favour nl_send_simple() to easly send a bunch of payload - * // encapsulated in a netlink message header. - * nl_send_simple(sk, MY_MSG_TYPE, 0, buf, sizeof(buf)); - * @endcode - * - * @par 3) Receiving data - * @code - * // nl_recv() receives a single message allocating a buffer for the message - * // content and gives back the pointer to you. - * struct sockaddr_nl peer; - * unsigned char *msg; - * nl_recv(sk, &peer, &msg); - * - * // nl_recvmsgs() receives a bunch of messages until the callback system - * // orders it to state, usually after receving a compolete multi part - * // message series. - * nl_recvmsgs(sk, my_callback_configuration); - * - * // nl_recvmsgs_default() acts just like nl_recvmsg() but uses the callback - * // configuration stored in the socket. - * nl_recvmsgs_default(sk); - * - * // In case you want to wait for the ACK to be recieved that you requested - * // with your latest message, you can call nl_wait_for_ack() - * nl_wait_for_ack(sk); - * @endcode - * - * @par 4) Closing - * @code - * // Close the socket first to release kernel memory - * nl_close(sk); - * @endcode - * - * @{ - */ - -#include <netlink-local.h> -#include <netlink/netlink.h> -#include <netlink/utils.h> -#include <netlink/handlers.h> -#include <netlink/msg.h> -#include <netlink/attr.h> - -/** - * @name Connection Management - * @{ - */ - -/** - * Create and connect netlink socket. - * @arg sk Netlink socket. - * @arg protocol Netlink protocol to use. - * - * Creates a netlink socket using the specified protocol, binds the socket - * and issues a connection attempt. - * - * @return 0 on success or a negative error code. - */ -int nl_connect(struct nl_sock *sk, int protocol) -{ - int err; - socklen_t addrlen; - - sk->s_fd = socket(AF_NETLINK, SOCK_RAW, protocol); - if (sk->s_fd < 0) { - err = -nl_syserr2nlerr(errno); - goto errout; - } - - if (!(sk->s_flags & NL_SOCK_BUFSIZE_SET)) { - err = nl_socket_set_buffer_size(sk, 0, 0); - if (err < 0) - goto errout; - } - - err = bind(sk->s_fd, (struct sockaddr*) &sk->s_local, - sizeof(sk->s_local)); - if (err < 0) { - err = -nl_syserr2nlerr(errno); - goto errout; - } - - addrlen = sizeof(sk->s_local); - err = getsockname(sk->s_fd, (struct sockaddr *) &sk->s_local, - &addrlen); - if (err < 0) { - err = -nl_syserr2nlerr(errno); - goto errout; - } - - if (addrlen != sizeof(sk->s_local)) { - err = -NLE_NOADDR; - goto errout; - } - - if (sk->s_local.nl_family != AF_NETLINK) { - err = -NLE_AF_NOSUPPORT; - goto errout; - } - - sk->s_proto = protocol; - - return 0; -errout: - close(sk->s_fd); - sk->s_fd = -1; - - return err; -} - -/** - * Close/Disconnect netlink socket. - * @arg sk Netlink socket. - */ -void nl_close(struct nl_sock *sk) -{ - if (sk->s_fd >= 0) { - close(sk->s_fd); - sk->s_fd = -1; - } - - sk->s_proto = 0; -} - -/** @} */ - -/** - * @name Send - * @{ - */ - -/** - * Send raw data over netlink socket. - * @arg sk Netlink socket. - * @arg buf Data buffer. - * @arg size Size of data buffer. - * @return Number of characters written on success or a negative error code. - */ -int nl_sendto(struct nl_sock *sk, void *buf, size_t size) -{ - int ret; - - ret = sendto(sk->s_fd, buf, size, 0, (struct sockaddr *) - &sk->s_peer, sizeof(sk->s_peer)); - if (ret < 0) - return -nl_syserr2nlerr(errno); - - return ret; -} - -/** - * Send netlink message with control over sendmsg() message header. - * @arg sk Netlink socket. - * @arg msg Netlink message to be sent. - * @arg hdr Sendmsg() message header. - * @return Number of characters sent on sucess or a negative error code. - */ -int nl_sendmsg(struct nl_sock *sk, struct nl_msg *msg, struct msghdr *hdr) -{ - struct nl_cb *cb; - int ret; - - struct iovec iov = { - .iov_base = (void *) nlmsg_hdr(msg), - .iov_len = nlmsg_hdr(msg)->nlmsg_len, - }; - - hdr->msg_iov = &iov; - hdr->msg_iovlen = 1; - - nlmsg_set_src(msg, &sk->s_local); - - cb = sk->s_cb; - if (cb->cb_set[NL_CB_MSG_OUT]) - if (nl_cb_call(cb, NL_CB_MSG_OUT, msg) != NL_OK) - return 0; - - ret = sendmsg(sk->s_fd, hdr, 0); - if (ret < 0) - return -nl_syserr2nlerr(errno); - - return ret; -} - - -/** - * Send netlink message. - * @arg sk Netlink socket. - * @arg msg Netlink message to be sent. - * @see nl_sendmsg() - * @return Number of characters sent on success or a negative error code. - */ -int nl_send(struct nl_sock *sk, struct nl_msg *msg) -{ - struct sockaddr_nl *dst; - struct ucred *creds; - - struct msghdr hdr = { - .msg_name = (void *) &sk->s_peer, - .msg_namelen = sizeof(struct sockaddr_nl), - }; - - /* Overwrite destination if specified in the message itself, defaults - * to the peer address of the socket. - */ - dst = nlmsg_get_dst(msg); - if (dst->nl_family == AF_NETLINK) - hdr.msg_name = dst; - - /* Add credentials if present. */ - creds = nlmsg_get_creds(msg); - if (creds != NULL) { - char buf[CMSG_SPACE(sizeof(struct ucred))]; - struct cmsghdr *cmsg; - - hdr.msg_control = buf; - hdr.msg_controllen = sizeof(buf); - - cmsg = CMSG_FIRSTHDR(&hdr); - cmsg->cmsg_level = SOL_SOCKET; - cmsg->cmsg_type = SCM_CREDENTIALS; - cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred)); - memcpy(CMSG_DATA(cmsg), creds, sizeof(struct ucred)); - } - - return nl_sendmsg(sk, msg, &hdr); -} - -/** - * Send netlink message and check & extend header values as needed. - * @arg sk Netlink socket. - * @arg msg Netlink message to be sent. - * - * Checks the netlink message \c nlh for completness and extends it - * as required before sending it out. Checked fields include pid, - * sequence nr, and flags. - * - * @see nl_send() - * @return Number of characters sent or a negative error code. - */ -int nl_send_auto_complete(struct nl_sock *sk, struct nl_msg *msg) -{ - struct nlmsghdr *nlh; - struct nl_cb *cb = sk->s_cb; - - nlh = nlmsg_hdr(msg); - if (nlh->nlmsg_pid == 0) - nlh->nlmsg_pid = sk->s_local.nl_pid; - - if (nlh->nlmsg_seq == 0) - nlh->nlmsg_seq = sk->s_seq_next++; - - if (msg->nm_protocol == -1) - msg->nm_protocol = sk->s_proto; - - nlh->nlmsg_flags |= NLM_F_REQUEST; - - if (!(sk->s_flags & NL_NO_AUTO_ACK)) - nlh->nlmsg_flags |= NLM_F_ACK; - - if (cb->cb_send_ow) - return cb->cb_send_ow(sk, msg); - else - return nl_send(sk, msg); -} - -/** - * Send simple netlink message using nl_send_auto_complete() - * @arg sk Netlink socket. - * @arg type Netlink message type. - * @arg flags Netlink message flags. - * @arg buf Data buffer. - * @arg size Size of data buffer. - * - * Builds a netlink message with the specified type and flags and - * appends the specified data as payload to the message. - * - * @see nl_send_auto_complete() - * @return Number of characters sent on success or a negative error code. - */ -int nl_send_simple(struct nl_sock *sk, int type, int flags, void *buf, - size_t size) -{ - int err; - struct nl_msg *msg; - - msg = nlmsg_alloc_simple(type, flags); - if (!msg) - return -NLE_NOMEM; - - if (buf && size) { - err = nlmsg_append(msg, buf, size, NLMSG_ALIGNTO); - if (err < 0) - goto errout; - } - - - err = nl_send_auto_complete(sk, msg); -errout: - nlmsg_free(msg); - - return err; -} - -/** @} */ - -/** - * @name Receive - * @{ - */ - -/** - * Receive data from netlink socket - * @arg sk Netlink socket. - * @arg nla Destination pointer for peer's netlink address. - * @arg buf Destination pointer for message content. - * @arg creds Destination pointer for credentials. - * - * Receives a netlink message, allocates a buffer in \c *buf and - * stores the message content. The peer's netlink address is stored - * in \c *nla. The caller is responsible for freeing the buffer allocated - * in \c *buf if a positive value is returned. Interruped system calls - * are handled by repeating the read. The input buffer size is determined - * by peeking before the actual read is done. - * - * A non-blocking sockets causes the function to return immediately with - * a return value of 0 if no data is available. - * - * @return Number of octets read, 0 on EOF or a negative error code. - */ -int nl_recv(struct nl_sock *sk, struct sockaddr_nl *nla, - unsigned char **buf, struct ucred **creds) -{ - int n; - int flags = 0; - static int page_size = 0; - struct iovec iov; - struct msghdr msg = { - .msg_name = (void *) nla, - .msg_namelen = sizeof(struct sockaddr_nl), - .msg_iov = &iov, - .msg_iovlen = 1, - .msg_control = NULL, - .msg_controllen = 0, - .msg_flags = 0, - }; - struct cmsghdr *cmsg; - - if (sk->s_flags & NL_MSG_PEEK) - flags |= MSG_PEEK; - - if (page_size == 0) - page_size = getpagesize(); - - iov.iov_len = page_size; - iov.iov_base = *buf = malloc(iov.iov_len); - - if (sk->s_flags & NL_SOCK_PASSCRED) { - msg.msg_controllen = CMSG_SPACE(sizeof(struct ucred)); - msg.msg_control = calloc(1, msg.msg_controllen); - } -retry: - - n = recvmsg(sk->s_fd, &msg, flags); - if (!n) - goto abort; - else if (n < 0) { - if (errno == EINTR) { - NL_DBG(3, "recvmsg() returned EINTR, retrying\n"); - goto retry; - } else if (errno == EAGAIN) { - NL_DBG(3, "recvmsg() returned EAGAIN, aborting\n"); - goto abort; - } else { - free(msg.msg_control); - free(*buf); - return -nl_syserr2nlerr(errno); - } - } - - if (iov.iov_len < n || - msg.msg_flags & MSG_TRUNC) { - /* Provided buffer is not long enough, enlarge it - * and try again. */ - iov.iov_len *= 2; - iov.iov_base = *buf = realloc(*buf, iov.iov_len); - goto retry; - } else if (msg.msg_flags & MSG_CTRUNC) { - msg.msg_controllen *= 2; - msg.msg_control = realloc(msg.msg_control, msg.msg_controllen); - goto retry; - } else if (flags != 0) { - /* Buffer is big enough, do the actual reading */ - flags = 0; - goto retry; - } - - if (msg.msg_namelen != sizeof(struct sockaddr_nl)) { - free(msg.msg_control); - free(*buf); - return -NLE_NOADDR; - } - - for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { - if (cmsg->cmsg_level == SOL_SOCKET && - cmsg->cmsg_type == SCM_CREDENTIALS) { - *creds = calloc(1, sizeof(struct ucred)); - memcpy(*creds, CMSG_DATA(cmsg), sizeof(struct ucred)); - break; - } - } - - free(msg.msg_control); - return n; - -abort: - free(msg.msg_control); - free(*buf); - return 0; -} - -#define NL_CB_CALL(cb, type, msg) \ -do { \ - err = nl_cb_call(cb, type, msg); \ - switch (err) { \ - case NL_OK: \ - err = 0; \ - break; \ - case NL_SKIP: \ - goto skip; \ - case NL_STOP: \ - goto stop; \ - default: \ - goto out; \ - } \ -} while (0) - -static int recvmsgs(struct nl_sock *sk, struct nl_cb *cb) -{ - int n, err = 0, multipart = 0; - unsigned char *buf = NULL; - struct nlmsghdr *hdr; - struct sockaddr_nl nla = {0}; - struct nl_msg *msg = NULL; - struct ucred *creds = NULL; - -continue_reading: - NL_DBG(3, "Attempting to read from %p\n", sk); - if (cb->cb_recv_ow) - n = cb->cb_recv_ow(sk, &nla, &buf, &creds); - else - n = nl_recv(sk, &nla, &buf, &creds); - - if (n <= 0) - return n; - - NL_DBG(3, "recvmsgs(%p): Read %d bytes\n", sk, n); - - hdr = (struct nlmsghdr *) buf; - while (nlmsg_ok(hdr, n)) { - NL_DBG(3, "recgmsgs(%p): Processing valid message...\n", sk); - - nlmsg_free(msg); - msg = nlmsg_convert(hdr); - if (!msg) { - err = -NLE_NOMEM; - goto out; - } - - nlmsg_set_proto(msg, sk->s_proto); - nlmsg_set_src(msg, &nla); - if (creds) - nlmsg_set_creds(msg, creds); - - /* Raw callback is the first, it gives the most control - * to the user and he can do his very own parsing. */ - if (cb->cb_set[NL_CB_MSG_IN]) - NL_CB_CALL(cb, NL_CB_MSG_IN, msg); - - /* Sequence number checking. The check may be done by - * the user, otherwise a very simple check is applied - * enforcing strict ordering */ - if (cb->cb_set[NL_CB_SEQ_CHECK]) - NL_CB_CALL(cb, NL_CB_SEQ_CHECK, msg); - else if (hdr->nlmsg_seq != sk->s_seq_expect) { - if (cb->cb_set[NL_CB_INVALID]) - NL_CB_CALL(cb, NL_CB_INVALID, msg); - else { - err = -NLE_SEQ_MISMATCH; - goto out; - } - } - - if (hdr->nlmsg_type == NLMSG_DONE || - hdr->nlmsg_type == NLMSG_ERROR || - hdr->nlmsg_type == NLMSG_NOOP || - hdr->nlmsg_type == NLMSG_OVERRUN) { - /* We can't check for !NLM_F_MULTI since some netlink - * users in the kernel are broken. */ - sk->s_seq_expect++; - NL_DBG(3, "recvmsgs(%p): Increased expected " \ - "sequence number to %d\n", - sk, sk->s_seq_expect); - } - - if (hdr->nlmsg_flags & NLM_F_MULTI) - multipart = 1; - - /* Other side wishes to see an ack for this message */ - if (hdr->nlmsg_flags & NLM_F_ACK) { - if (cb->cb_set[NL_CB_SEND_ACK]) - NL_CB_CALL(cb, NL_CB_SEND_ACK, msg); - else { - /* FIXME: implement */ - } - } - - /* messages terminates a multpart message, this is - * usually the end of a message and therefore we slip - * out of the loop by default. the user may overrule - * this action by skipping this packet. */ - if (hdr->nlmsg_type == NLMSG_DONE) { - multipart = 0; - if (cb->cb_set[NL_CB_FINISH]) - NL_CB_CALL(cb, NL_CB_FINISH, msg); - } - - /* Message to be ignored, the default action is to - * skip this message if no callback is specified. The - * user may overrule this action by returning - * NL_PROCEED. */ - else if (hdr->nlmsg_type == NLMSG_NOOP) { - if (cb->cb_set[NL_CB_SKIPPED]) - NL_CB_CALL(cb, NL_CB_SKIPPED, msg); - else - goto skip; - } - - /* Data got lost, report back to user. The default action is to - * quit parsing. The user may overrule this action by retuning - * NL_SKIP or NL_PROCEED (dangerous) */ - else if (hdr->nlmsg_type == NLMSG_OVERRUN) { - if (cb->cb_set[NL_CB_OVERRUN]) - NL_CB_CALL(cb, NL_CB_OVERRUN, msg); - else { - err = -NLE_MSG_OVERFLOW; - goto out; - } - } - - /* Message carries a nlmsgerr */ - else if (hdr->nlmsg_type == NLMSG_ERROR) { - struct nlmsgerr *e = nlmsg_data(hdr); - - if (hdr->nlmsg_len < nlmsg_msg_size(sizeof(*e))) { - /* Truncated error message, the default action - * is to stop parsing. The user may overrule - * this action by returning NL_SKIP or - * NL_PROCEED (dangerous) */ - if (cb->cb_set[NL_CB_INVALID]) - NL_CB_CALL(cb, NL_CB_INVALID, msg); - else { - err = -NLE_MSG_TRUNC; - goto out; - } - } else if (e->error) { - /* Error message reported back from kernel. */ - if (cb->cb_err) { - err = cb->cb_err(&nla, e, - cb->cb_err_arg); - if (err < 0) - goto out; - else if (err == NL_SKIP) - goto skip; - else if (err == NL_STOP) { - err = -nl_syserr2nlerr(e->error); - goto out; - } - } else { - err = -nl_syserr2nlerr(e->error); - goto out; - } - } else if (cb->cb_set[NL_CB_ACK]) - NL_CB_CALL(cb, NL_CB_ACK, msg); - } else { - /* Valid message (not checking for MULTIPART bit to - * get along with broken kernels. NL_SKIP has no - * effect on this. */ - if (cb->cb_set[NL_CB_VALID]) - NL_CB_CALL(cb, NL_CB_VALID, msg); - } -skip: - err = 0; - hdr = nlmsg_next(hdr, &n); - } - - nlmsg_free(msg); - free(buf); - free(creds); - buf = NULL; - msg = NULL; - creds = NULL; - - if (multipart) { - /* Multipart message not yet complete, continue reading */ - goto continue_reading; - } -stop: - err = 0; -out: - nlmsg_free(msg); - free(buf); - free(creds); - - return err; -} - -/** - * Receive a set of messages from a netlink socket. - * @arg sk Netlink socket. - * @arg cb set of callbacks to control behaviour. - * - * Repeatedly calls nl_recv() or the respective replacement if provided - * by the application (see nl_cb_overwrite_recv()) and parses the - * received data as netlink messages. Stops reading if one of the - * callbacks returns NL_STOP or nl_recv returns either 0 or a negative error code. - * - * A non-blocking sockets causes the function to return immediately if - * no data is available. - * - * @return 0 on success or a negative error code from nl_recv(). - */ -int nl_recvmsgs(struct nl_sock *sk, struct nl_cb *cb) -{ - if (cb->cb_recvmsgs_ow) - return cb->cb_recvmsgs_ow(sk, cb); - else - return recvmsgs(sk, cb); -} - - -static int ack_wait_handler(struct nl_msg *msg, void *arg) -{ - return NL_STOP; -} - -/** - * Wait for ACK. - * @arg sk Netlink socket. - * @pre The netlink socket must be in blocking state. - * - * Waits until an ACK is received for the latest not yet acknowledged - * netlink message. - */ -int nl_wait_for_ack(struct nl_sock *sk) -{ - int err; - struct nl_cb *cb; - - cb = nl_cb_clone(sk->s_cb); - if (cb == NULL) - return -NLE_NOMEM; - - nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_wait_handler, NULL); - err = nl_recvmsgs(sk, cb); - nl_cb_put(cb); - - return err; -} - -/** @} */ - -/** @} */ |