+++ /dev/null
-/*
- * 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) 2003-2006 Thomas Graf <tgraf@suug.ch>
- */
-
-/**
- * @ingroup nl
- * @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 1) Creating a new netlink message
- * @code
- * // The most common way to start creating a message is by providing an
- * // defined netlink header to nlmsg_build():
- * struct nlmsghdr hdr = {
- * .nlmsg_type = MY_TYPE,
- * .nlmsg_flags = MY_FLAGS,
- * };
- * struct nl_msg *msg = nlmsg_build(&hdr);
- *
- * // For simple usages where only the message type and flags is of
- * // interenst a shortcut can be taken:
- * struct nl_msg *msg = nlmsg_build_simple(MY_TYPE, MY_FLAGS);
- *
- * // When using a headerless message for creating nested attributes
- * // the header is not required and nlmsg_build_no_hdr() may be used:
- * struct nl_msg *msg = nlmsg_build_no_hdr();
- *
- * // The header can later be retrieved with nlmsg_hdr() and changed again:
- * nlmsg_hdr(msg)->nlmsg_flags |= YET_ANOTHER_FLAG;
- * @endcode
- *
- * @par 2) Appending data to the message
- * @code
- * // Payload may be added to the message via nlmsg_append(). The fourth
- * // parameter specifies whether to pad up to NLMSG_ALIGN to make sure
- * // that a possible further data block is properly aligned.
- * nlmsg_append(msg, &mydata, sizeof(mydata), 0);
- * @endcode
- *
- * @par 3) Cleaning up message construction
- * @code
- * // After successful use of the message, the memory must be freed
- * // using nlmsg_free()
- * nlmsg_free(msg);
- * @endcode
- *
- * @par Example 2 (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 <linux/socket.h>
-
-/**
- * @name Size Calculations
- * @{
- */
-
-/**
- * length of netlink message not including padding
- * @arg payload length of message payload
- */
-int nlmsg_msg_size(int payload)
-{
- return NLMSG_HDRLEN + payload;
-}
-
-/**
- * length of netlink message including padding
- * @arg payload length of message payload
- */
-int nlmsg_total_size(int payload)
-{
- return NLMSG_ALIGN(nlmsg_msg_size(payload));
-}
-
-/**
- * length of padding at the message's tail
- * @arg payload length of message payload
- */
-int nlmsg_padlen(int payload)
-{
- return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
-}
-
-/** @} */
-
-/**
- * @name Payload Access
- * @{
- */
-
-/**
- * head of message payload
- * @arg nlh netlink messsage header
- */
-void *nlmsg_data(const struct nlmsghdr *nlh)
-{
- return (unsigned char *) nlh + NLMSG_HDRLEN;
-}
-
-void *nlmsg_tail(const struct nlmsghdr *nlh)
-{
- return (unsigned char *) nlh + NLMSG_ALIGN(nlh->nlmsg_len);
-}
-
-/**
- * length of message payload
- * @arg nlh netlink message header
- */
-int nlmsg_len(const struct nlmsghdr *nlh)
-{
- return nlh->nlmsg_len - NLMSG_HDRLEN;
-}
-
-/** @} */
-
-/**
- * @name Attribute Access
- * @{
- */
-
-/**
- * head of attributes data
- * @arg nlh netlink message header
- * @arg hdrlen length of family specific header
- */
-struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh, int hdrlen)
-{
- unsigned char *data = nlmsg_data(nlh);
- return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
-}
-
-/**
- * length of attributes data
- * @arg nlh netlink message header
- * @arg hdrlen length of family specific header
- */
-int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
-{
- return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
-}
-
-/** @} */
-
-/**
- * @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 (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
- return nl_errno(EINVAL);
-
- return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
- nlmsg_attrlen(nlh, hdrlen), policy);
-}
-
-/**
- * nlmsg_find_attr - find a specific attribute in a netlink message
- * @arg nlh netlink message header
- * @arg hdrlen length of familiy specific header
- * @arg attrtype type of attribute to look for
- *
- * Returns the first attribute which matches the specified type.
- */
-struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh, int hdrlen, int attrtype)
-{
- return nla_find(nlmsg_attrdata(nlh, hdrlen),
- nlmsg_attrlen(nlh, hdrlen), attrtype);
-}
-
-/**
- * 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 (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
- return nl_errno(EINVAL);
-
- return nla_validate(nlmsg_attrdata(nlh, hdrlen),
- nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
-}
-
-/** @} */
-
-/**
- * @name Message Building/Access
- * @{
- */
-
-struct nl_msg *nlmsg_new(void)
-{
- struct nl_msg *nm;
-
- nm = calloc(1, sizeof(*nm));
- if (!nm)
- goto errout;
-
- nm->nm_nlh = calloc(1, nlmsg_msg_size(0));
- if (!nm->nm_nlh)
- goto errout;
-
- nm->nm_nlh->nlmsg_len = nlmsg_msg_size(0);
- return nm;
-errout:
- free(nm);
- nl_errno(ENOMEM);
- return NULL;
-}
-
-
-/**
- * Build a new netlink message
- * @arg hdr Netlink message header template
- *
- * Builds a new netlink message with a tailroom for the netlink
- * 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_build(struct nlmsghdr *hdr)
-{
- struct nl_msg *nm;
-
- nm = nlmsg_new();
- if (nm && hdr) {
- int size = nm->nm_nlh->nlmsg_len;
- memcpy(nm->nm_nlh, hdr, sizeof(*hdr));
- nm->nm_nlh->nlmsg_len = size;
- }
-
- return nm;
-}
-
-struct nl_msg *nlmsg_build_simple(int nlmsgtype, int flags)
-{
- struct nlmsghdr nlh = {
- .nlmsg_type = nlmsgtype,
- .nlmsg_flags = flags,
- };
-
- return nlmsg_build(&nlh);
-}
-
-struct nl_msg *nlmsg_build_no_hdr(void)
-{
- return nlmsg_build(NULL);
-}
-
-struct nl_msg *nlmsg_convert(struct nlmsghdr *hdr)
-{
- struct nl_msg *nm;
-
- nm = calloc(1, sizeof(struct nl_msg));
- if (!nm)
- goto errout;
-
- nm->nm_nlh = calloc(1, NLMSG_ALIGN(hdr->nlmsg_len));
- if (!nm->nm_nlh)
- goto errout;
-
- memcpy(nm->nm_nlh, hdr, NLMSG_ALIGN(hdr->nlmsg_len));
-
- return nm;
-errout:
- free(nm);
- nl_errno(ENOMEM);
- return NULL;
-}
-
-/**
- * Append raw data to a netlink message
- * @arg n netlink message
- * @arg data data to add
- * @arg len length of data
- * @arg pad add padding at the end?
- *
- * Extends the netlink message as needed and appends the data of given
- * length to the message. The length of the message is not aligned to
- * anything. The caller is responsible to provide a length and
- * evtentually padded data to fullfil any alignment requirements.
- *
- * @return 0 on success or a negative error code
- * @attention Appending of improperly aligned raw data may result in
- * a corrupt message. It is left to you to add the right
- * amount of data to have the message aligned to NLMSG_ALIGNTO
- * in the end.
- */
-int nlmsg_append(struct nl_msg *n, void *data, size_t len, int pad)
-{
- void *tmp;
-
- if (pad)
- len = NLMSG_ALIGN(len);
-
- tmp = realloc(n->nm_nlh, n->nm_nlh->nlmsg_len + len);
- if (!tmp)
- return nl_errno(ENOMEM);
-
- n->nm_nlh = tmp;
- memcpy((void *) n->nm_nlh + n->nm_nlh->nlmsg_len, data, len);
- n->nm_nlh->nlmsg_len += len;
-
- return 0;
-}
-
-
-/**
- * nlmsg_put - Add a netlink message header
- * @arg n netlink message
- * @arg pid netlink process id
- * @arg seq sequence number of message
- * @arg type message type
- * @arg payload length of message payload
- * @arg flags message flags
- */
-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_len = nlmsg_msg_size(payload);
- nlh->nlmsg_flags = flags;
- nlh->nlmsg_pid = pid;
- nlh->nlmsg_seq = seq;
-
- memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
- nlmsg_padlen(payload));
-
- return nlh;
-}
-
-/**
- * Return actual netlink message
- * @arg n netlink message
- *
- * Returns the actual netlink message casted to the type of the netlink
- * message header.
- *
- * @return A pointer to the netlink message.
- */
-struct nlmsghdr *nlmsg_hdr(struct nl_msg *n)
-{
- return n->nm_nlh;
-}
-
-/**
- * Free a netlink message
- * @arg n netlink message
- *
- * Destroys a netlink message and frees up all used memory.
- *
- * @pre The message must be unused.
- */
-void nlmsg_free(struct nl_msg *n)
-{
- if (!n)
- return;
-
- free(n->nm_nlh);
- free(n);
-}
-
-/** @} */
-
-/**
- * @name Attribute Modification
- * @{
- */
-
-void nlmsg_set_proto(struct nl_msg *msg, int protocol)
-{
- msg->nm_protocol = protocol;
-}
-
-int nlmsg_get_proto(struct nl_msg *msg)
-{
- return msg->nm_protocol;
-}
-
-void nlmsg_set_src(struct nl_msg *msg, struct sockaddr_nl *addr)
-{
- memcpy(&msg->nm_src, addr, sizeof(*addr));
-}
-
-struct sockaddr_nl *nlmsg_get_src(struct nl_msg *msg)
-{
- return &msg->nm_src;
-}
-
-void nlmsg_set_dst(struct nl_msg *msg, struct sockaddr_nl *addr)
-{
- memcpy(&msg->nm_dst, addr, sizeof(*addr));
-}
-
-struct sockaddr_nl *nlmsg_get_dst(struct nl_msg *msg)
-{
- return &msg->nm_dst;
-}
-
-void nlmsg_set_creds(struct nl_msg *msg, struct ucred *creds)
-{
- memcpy(&msg->nm_creds, creds, sizeof(*creds));
- msg->nm_flags |= NL_MSG_CRED_PRESENT;
-}
-
-struct ucred *nlmsg_get_creds(struct nl_msg *msg)
-{
- if (msg->nm_flags & NL_MSG_CRED_PRESENT)
- return &msg->nm_creds;
- return NULL;
-}
-
-/** @} */
-
-/**
- * @name Netlink Message Type Translations
- * @{
- */
-
-static struct trans_tbl nl_msgtypes[] = {
- __ADD(NLMSG_NOOP,NOOP)
- __ADD(NLMSG_ERROR,ERROR)
- __ADD(NLMSG_DONE,DONE)
- __ADD(NLMSG_OVERRUN,OVERRUN)
-};
-
-/**
- * Convert netlink message type number to character string.
- * @arg type Netlink message type.
- * @arg buf Destination buffer.
- * @arg size Size of destination buffer.
- *
- * Converts a netlink message type number to a character string and stores
- * it in the provided buffer.
- *
- * @return The destination buffer or the type encoded in hexidecimal form
- * if no match was found.
- */
-char *nl_nlmsgtype2str(int type, char *buf, size_t size)
-{
- return __type2str(type, buf, size, nl_msgtypes,
- ARRAY_SIZE(nl_msgtypes));
-}
-
-/**
- * Convert character string to netlink message type.
- * @arg name Name of netlink message type.
- *
- * Converts the provided character string specifying a netlink message type
- * into the corresponding numeric value
- *
- * @return Numeric netlink message type or a negative value
- * if no match was found.
- */
-int nl_str2nlmsgtype(const char *name)
-{
- return __str2type(name, nl_msgtypes, ARRAY_SIZE(nl_msgtypes));
-}
-
-/** @} */
-
-/**
- * @name Netlink Message Flags Translations
- * @{
- */
-
-/**
- * Translate netlink message flags into a character string (Reentrant).
- * @arg flags netlink message flags
- * @arg buf destination buffer
- * @arg len buffer length
- *
- * Translates netlink message flags into a character string and stores
- * it in the provided buffer.
- *
- * @return The destination buffer
- */
-char *nl_nlmsg_flags2str(int flags, char *buf, size_t len)
-{
- memset(buf, 0, len);
-
-#define PRINT_FLAG(f) \
- if (flags & NLM_F_##f) { \
- flags &= ~NLM_F_##f; \
- strncat(buf, #f, len - strlen(buf) - 1); \
- if (flags) \
- strncat(buf, ",", len - strlen(buf) - 1); \
- }
-
- PRINT_FLAG(REQUEST);
- PRINT_FLAG(MULTI);
- PRINT_FLAG(ACK);
- PRINT_FLAG(ECHO);
- PRINT_FLAG(ROOT);
- PRINT_FLAG(MATCH);
- PRINT_FLAG(ATOMIC);
- PRINT_FLAG(REPLACE);
- PRINT_FLAG(EXCL);
- PRINT_FLAG(CREATE);
- PRINT_FLAG(APPEND);
-
- if (flags) {
- char s[32];
- snprintf(s, sizeof(s), "0x%x", flags);
- strncat(buf, s, len - strlen(buf) - 1);
- }
-#undef PRINT_FLAG
-
- return buf;
-}
-
-/** @} */
-
-/**
- * @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);
- nl_object_put(obj);
- 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_mngt_associate(nlmsg_get_proto(msg),
- nlmsg_hdr(msg)->nlmsg_type);
- if (ops == NULL)
- return nl_error(ENOENT, "Unknown message type %d",
- nlmsg_hdr(msg)->nlmsg_type);
- p.pp_arg = &x;
-
- return nl_cache_parse(ops, NULL, nlmsg_hdr(msg), &p);
-}
-
-/** @} */
-
-/** @} */
git://git.onelab.eu / libnl.git / blobdiff