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Diffstat (limited to 'package/libs/libnl-tiny/src/msg.c')
-rw-r--r-- | package/libs/libnl-tiny/src/msg.c | 561 |
1 files changed, 0 insertions, 561 deletions
diff --git a/package/libs/libnl-tiny/src/msg.c b/package/libs/libnl-tiny/src/msg.c deleted file mode 100644 index b502047c4c..0000000000 --- a/package/libs/libnl-tiny/src/msg.c +++ /dev/null @@ -1,561 +0,0 @@ -/* - * lib/msg.c Netlink Messages 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> - */ - -/** - * @ingroup core - * @defgroup msg Messages - * Netlink Message Construction/Parsing Interface - * - * The following information is partly extracted from RFC3549 - * (ftp://ftp.rfc-editor.org/in-notes/rfc3549.txt) - * - * @par Message Format - * Netlink messages consist of a byte stream with one or multiple - * Netlink headers and an associated payload. If the payload is too big - * to fit into a single message it, can be split over multiple Netlink - * messages, collectively called a multipart message. For multipart - * messages, the first and all following headers have the \c NLM_F_MULTI - * Netlink header flag set, except for the last header which has the - * Netlink header type \c NLMSG_DONE. - * - * @par - * The Netlink message header (\link nlmsghdr struct nlmsghdr\endlink) is shown below. - * @code - * 0 1 2 3 - * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | Length | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | Type | Flags | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | Sequence Number | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | Process ID (PID) | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * @endcode - * - * @par - * The netlink message header and payload must be aligned properly: - * @code - * <------- NLMSG_ALIGN(hlen) ------> <---- NLMSG_ALIGN(len) ---> - * +----------------------------+- - -+- - - - - - - - - - -+- - -+ - * | Header | Pad | Payload | Pad | - * | struct nlmsghdr | | | | - * +----------------------------+- - -+- - - - - - - - - - -+- - -+ - * @endcode - * @par - * Message Format: - * @code - * <--- nlmsg_total_size(payload) ---> - * <-- nlmsg_msg_size(payload) -> - * +----------+- - -+-------------+- - -+-------- - - - * | nlmsghdr | Pad | Payload | Pad | nlmsghdr - * +----------+- - -+-------------+- - -+-------- - - - * nlmsg_data(nlh)---^ ^ - * nlmsg_next(nlh)-----------------------+ - * @endcode - * @par - * The payload may consist of arbitary data but may have strict - * alignment and formatting rules depening on the specific netlink - * families. - * @par - * @code - * <---------------------- nlmsg_len(nlh) ---------------------> - * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) -> - * +----------------------+- - -+--------------------------------+ - * | Family Header | Pad | Attributes | - * +----------------------+- - -+--------------------------------+ - * nlmsg_attrdata(nlh, hdrlen)---^ - * @endcode - * @par The ACK Netlink Message - * This message is actually used to denote both an ACK and a NACK. - * Typically, the direction is from FEC to CPC (in response to an ACK - * request message). However, the CPC should be able to send ACKs back - * to FEC when requested. - * @code - * 0 1 2 3 - * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | Netlink message header | - * | type = NLMSG_ERROR | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | Error code | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | OLD Netlink message header | - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * @endcode - * - * @par Example - * @code - * // Various methods exist to create/allocate a new netlink - * // message. - * // - * // nlmsg_alloc() will allocate an empty netlink message with - * // a maximum payload size which defaults to the page size of - * // the system. This default size can be modified using the - * // function nlmsg_set_default_size(). - * struct nl_msg *msg = nlmsg_alloc(); - * - * // Very often, the message type and message flags are known - * // at allocation time while the other fields are auto generated: - * struct nl_msg *msg = nlmsg_alloc_simple(MY_TYPE, MY_FLAGS); - * - * // Alternatively an existing netlink message header can be used - * // to inherit the header values: - * struct nlmsghdr hdr = { - * .nlmsg_type = MY_TYPE, - * .nlmsg_flags = MY_FLAGS, - * }; - * struct nl_msg *msg = nlmsg_inherit(&hdr); - * - * // Last but not least, netlink messages received from netlink sockets - * // can be converted into nl_msg objects using nlmsg_convert(). This - * // will create a message with a maximum payload size which equals the - * // length of the existing netlink message, therefore no more data can - * // be appened without calling nlmsg_expand() first. - * struct nl_msg *msg = nlmsg_convert(nlh_from_nl_sock); - * - * // Payload may be added to the message via nlmsg_append(). The fourth - * // parameter specifies the number of alignment bytes the data should - * // be padding with at the end. Common values are 0 to disable it or - * // NLMSG_ALIGNTO to ensure proper netlink message padding. - * nlmsg_append(msg, &mydata, sizeof(mydata), 0); - * - * // Sometimes it may be necessary to reserve room for data but defer - * // the actual copying to a later point, nlmsg_reserve() can be used - * // for this purpose: - * void *data = nlmsg_reserve(msg, sizeof(mydata), NLMSG_ALIGNTO); - * - * // Attributes may be added using the attributes interface. - * - * // After successful use of the message, the memory must be freed - * // using nlmsg_free() - * nlmsg_free(msg); - * @endcode - * - * @par 4) Parsing messages - * @code - * int n; - * unsigned char *buf; - * struct nlmsghdr *hdr; - * - * n = nl_recv(handle, NULL, &buf); - * - * hdr = (struct nlmsghdr *) buf; - * while (nlmsg_ok(hdr, n)) { - * // Process message here... - * hdr = nlmsg_next(hdr, &n); - * } - * @endcode - * @{ - */ - -#include <netlink-local.h> -#include <netlink/netlink.h> -#include <netlink/utils.h> -#include <netlink/cache.h> -#include <netlink/attr.h> -#include <netlink/msg.h> -#include <linux/socket.h> - -static size_t default_msg_size = 4096; - -/** - * @name Attribute Access - * @{ - */ - -//** @} */ - -/** - * @name Message Parsing - * @{ - */ - -/** - * check if the netlink message fits into the remaining bytes - * @arg nlh netlink message header - * @arg remaining number of bytes remaining in message stream - */ -int nlmsg_ok(const struct nlmsghdr *nlh, int remaining) -{ - return (remaining >= sizeof(struct nlmsghdr) && - nlh->nlmsg_len >= sizeof(struct nlmsghdr) && - nlh->nlmsg_len <= remaining); -} - -/** - * next netlink message in message stream - * @arg nlh netlink message header - * @arg remaining number of bytes remaining in message stream - * - * @returns the next netlink message in the message stream and - * decrements remaining by the size of the current message. - */ -struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining) -{ - int totlen = NLMSG_ALIGN(nlh->nlmsg_len); - - *remaining -= totlen; - - return (struct nlmsghdr *) ((unsigned char *) nlh + totlen); -} - -/** - * parse attributes of a netlink message - * @arg nlh netlink message header - * @arg hdrlen length of family specific header - * @arg tb destination array with maxtype+1 elements - * @arg maxtype maximum attribute type to be expected - * @arg policy validation policy - * - * See nla_parse() - */ -int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen, struct nlattr *tb[], - int maxtype, struct nla_policy *policy) -{ - if (!nlmsg_valid_hdr(nlh, hdrlen)) - return -NLE_MSG_TOOSHORT; - - return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen), - nlmsg_attrlen(nlh, hdrlen), policy); -} - -/** - * nlmsg_validate - validate a netlink message including attributes - * @arg nlh netlinket message header - * @arg hdrlen length of familiy specific header - * @arg maxtype maximum attribute type to be expected - * @arg policy validation policy - */ -int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype, - struct nla_policy *policy) -{ - if (!nlmsg_valid_hdr(nlh, hdrlen)) - return -NLE_MSG_TOOSHORT; - - return nla_validate(nlmsg_attrdata(nlh, hdrlen), - nlmsg_attrlen(nlh, hdrlen), maxtype, policy); -} - -/** @} */ - -/** - * @name Message Building/Access - * @{ - */ - -static struct nl_msg *__nlmsg_alloc(size_t len) -{ - struct nl_msg *nm; - - nm = calloc(1, sizeof(*nm)); - if (!nm) - goto errout; - - nm->nm_refcnt = 1; - - nm->nm_nlh = malloc(len); - if (!nm->nm_nlh) - goto errout; - - memset(nm->nm_nlh, 0, sizeof(struct nlmsghdr)); - - nm->nm_protocol = -1; - nm->nm_size = len; - nm->nm_nlh->nlmsg_len = nlmsg_total_size(0); - - NL_DBG(2, "msg %p: Allocated new message, maxlen=%zu\n", nm, len); - - return nm; -errout: - free(nm); - return NULL; -} - -/** - * Allocate a new netlink message with the default maximum payload size. - * - * Allocates a new netlink message without any further payload. The - * maximum payload size defaults to PAGESIZE or as otherwise specified - * with nlmsg_set_default_size(). - * - * @return Newly allocated netlink message or NULL. - */ -struct nl_msg *nlmsg_alloc(void) -{ - return __nlmsg_alloc(default_msg_size); -} - -/** - * Allocate a new netlink message with maximum payload size specified. - */ -struct nl_msg *nlmsg_alloc_size(size_t max) -{ - return __nlmsg_alloc(max); -} - -/** - * Allocate a new netlink message and inherit netlink message header - * @arg hdr Netlink message header template - * - * Allocates a new netlink message and inherits the original message - * header. If \a hdr is not NULL it will be used as a template for - * the netlink message header, otherwise the header is left blank. - * - * @return Newly allocated netlink message or NULL - */ -struct nl_msg *nlmsg_inherit(struct nlmsghdr *hdr) -{ - struct nl_msg *nm; - - nm = nlmsg_alloc(); - if (nm && hdr) { - struct nlmsghdr *new = nm->nm_nlh; - - new->nlmsg_type = hdr->nlmsg_type; - new->nlmsg_flags = hdr->nlmsg_flags; - new->nlmsg_seq = hdr->nlmsg_seq; - new->nlmsg_pid = hdr->nlmsg_pid; - } - - return nm; -} - -/** - * Allocate a new netlink message - * @arg nlmsgtype Netlink message type - * @arg flags Message flags. - * - * @return Newly allocated netlink message or NULL. - */ -struct nl_msg *nlmsg_alloc_simple(int nlmsgtype, int flags) -{ - struct nl_msg *msg; - struct nlmsghdr nlh = { - .nlmsg_type = nlmsgtype, - .nlmsg_flags = flags, - }; - - msg = nlmsg_inherit(&nlh); - if (msg) - NL_DBG(2, "msg %p: Allocated new simple message\n", msg); - - return msg; -} - -/** - * Set the default maximum message payload size for allocated messages - * @arg max Size of payload in bytes. - */ -void nlmsg_set_default_size(size_t max) -{ - if (max < nlmsg_total_size(0)) - max = nlmsg_total_size(0); - - default_msg_size = max; -} - -/** - * Convert a netlink message received from a netlink socket to a nl_msg - * @arg hdr Netlink message received from netlink socket. - * - * Allocates a new netlink message and copies all of the data pointed to - * by \a hdr into the new message object. - * - * @return Newly allocated netlink message or NULL. - */ -struct nl_msg *nlmsg_convert(struct nlmsghdr *hdr) -{ - struct nl_msg *nm; - - nm = __nlmsg_alloc(NLMSG_ALIGN(hdr->nlmsg_len)); - if (!nm) - goto errout; - - memcpy(nm->nm_nlh, hdr, hdr->nlmsg_len); - - return nm; -errout: - nlmsg_free(nm); - return NULL; -} - -/** - * Reserve room for additional data in a netlink message - * @arg n netlink message - * @arg len length of additional data to reserve room for - * @arg pad number of bytes to align data to - * - * Reserves room for additional data at the tail of the an - * existing netlink message. Eventual padding required will - * be zeroed out. - * - * @return Pointer to start of additional data tailroom or NULL. - */ -void *nlmsg_reserve(struct nl_msg *n, size_t len, int pad) -{ - void *buf = n->nm_nlh; - size_t nlmsg_len = n->nm_nlh->nlmsg_len; - size_t tlen; - - tlen = pad ? ((len + (pad - 1)) & ~(pad - 1)) : len; - - if ((tlen + nlmsg_len) > n->nm_size) - return NULL; - - buf += nlmsg_len; - n->nm_nlh->nlmsg_len += tlen; - - if (tlen > len) - memset(buf + len, 0, tlen - len); - - NL_DBG(2, "msg %p: Reserved %zu bytes, pad=%d, nlmsg_len=%d\n", - n, len, pad, n->nm_nlh->nlmsg_len); - - return buf; -} - -/** - * Append data to tail of a netlink message - * @arg n netlink message - * @arg data data to add - * @arg len length of data - * @arg pad Number of bytes to align data to. - * - * Extends the netlink message as needed and appends the data of given - * length to the message. - * - * @return 0 on success or a negative error code - */ -int nlmsg_append(struct nl_msg *n, void *data, size_t len, int pad) -{ - void *tmp; - - tmp = nlmsg_reserve(n, len, pad); - if (tmp == NULL) - return -NLE_NOMEM; - - memcpy(tmp, data, len); - NL_DBG(2, "msg %p: Appended %zu bytes with padding %d\n", n, len, pad); - - return 0; -} - -/** - * Add a netlink message header to a netlink message - * @arg n netlink message - * @arg pid netlink process id or NL_AUTO_PID - * @arg seq sequence number of message or NL_AUTO_SEQ - * @arg type message type - * @arg payload length of message payload - * @arg flags message flags - * - * Adds or overwrites the netlink message header in an existing message - * object. If \a payload is greater-than zero additional room will be - * reserved, f.e. for family specific headers. It can be accesed via - * nlmsg_data(). - * - * @return A pointer to the netlink message header or NULL. - */ -struct nlmsghdr *nlmsg_put(struct nl_msg *n, uint32_t pid, uint32_t seq, - int type, int payload, int flags) -{ - struct nlmsghdr *nlh; - - if (n->nm_nlh->nlmsg_len < NLMSG_HDRLEN) - BUG(); - - nlh = (struct nlmsghdr *) n->nm_nlh; - nlh->nlmsg_type = type; - nlh->nlmsg_flags = flags; - nlh->nlmsg_pid = pid; - nlh->nlmsg_seq = seq; - - NL_DBG(2, "msg %p: Added netlink header type=%d, flags=%d, pid=%d, " - "seq=%d\n", n, type, flags, pid, seq); - - if (payload > 0 && - nlmsg_reserve(n, payload, NLMSG_ALIGNTO) == NULL) - return NULL; - - return nlh; -} - -/** - * Release a reference from an netlink message - * @arg msg message to release reference from - * - * Frees memory after the last reference has been released. - */ -void nlmsg_free(struct nl_msg *msg) -{ - if (!msg) - return; - - msg->nm_refcnt--; - NL_DBG(4, "Returned message reference %p, %d remaining\n", - msg, msg->nm_refcnt); - - if (msg->nm_refcnt < 0) - BUG(); - - if (msg->nm_refcnt <= 0) { - free(msg->nm_nlh); - free(msg); - NL_DBG(2, "msg %p: Freed\n", msg); - } -} - -/** @} */ - -/** - * @name Direct Parsing - * @{ - */ - -/** @cond SKIP */ -struct dp_xdata { - void (*cb)(struct nl_object *, void *); - void *arg; -}; -/** @endcond */ - -static int parse_cb(struct nl_object *obj, struct nl_parser_param *p) -{ - struct dp_xdata *x = p->pp_arg; - - x->cb(obj, x->arg); - return 0; -} - -int nl_msg_parse(struct nl_msg *msg, void (*cb)(struct nl_object *, void *), - void *arg) -{ - struct nl_cache_ops *ops; - struct nl_parser_param p = { - .pp_cb = parse_cb - }; - struct dp_xdata x = { - .cb = cb, - .arg = arg, - }; - - ops = nl_cache_ops_associate(nlmsg_get_proto(msg), - nlmsg_hdr(msg)->nlmsg_type); - if (ops == NULL) - return -NLE_MSGTYPE_NOSUPPORT; - p.pp_arg = &x; - - return nl_cache_parse(ops, NULL, nlmsg_hdr(msg), &p); -} - -/** @} */ |