2 * lib/msg.c Netlink Messages Interface
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation version 2.1
9 * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
14 * @defgroup msg Messages
15 * Netlink Message Construction/Parsing Interface
17 * The following information is partly extracted from RFC3549
18 * (ftp://ftp.rfc-editor.org/in-notes/rfc3549.txt)
21 * Netlink messages consist of a byte stream with one or multiple
22 * Netlink headers and an associated payload. If the payload is too big
23 * to fit into a single message it, can be split over multiple Netlink
24 * messages, collectively called a multipart message. For multipart
25 * messages, the first and all following headers have the \c NLM_F_MULTI
26 * Netlink header flag set, except for the last header which has the
27 * Netlink header type \c NLMSG_DONE.
30 * The Netlink message header (\link nlmsghdr struct nlmsghdr\endlink) is shown below.
33 * 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
34 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
40 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
41 * | Process ID (PID) |
42 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46 * The netlink message header and payload must be aligned properly:
48 * <------- NLMSG_ALIGN(hlen) ------> <---- NLMSG_ALIGN(len) --->
49 * +----------------------------+- - -+- - - - - - - - - - -+- - -+
50 * | Header | Pad | Payload | Pad |
51 * | struct nlmsghdr | | | |
52 * +----------------------------+- - -+- - - - - - - - - - -+- - -+
57 * <--- nlmsg_total_size(payload) --->
58 * <-- nlmsg_msg_size(payload) ->
59 * +----------+- - -+-------------+- - -+-------- - -
60 * | nlmsghdr | Pad | Payload | Pad | nlmsghdr
61 * +----------+- - -+-------------+- - -+-------- - -
62 * nlmsg_data(nlh)---^ ^
63 * nlmsg_next(nlh)-----------------------+
66 * The payload may consist of arbitary data but may have strict
67 * alignment and formatting rules depening on the specific netlink
71 * <---------------------- nlmsg_len(nlh) --------------------->
72 * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
73 * +----------------------+- - -+--------------------------------+
74 * | Family Header | Pad | Attributes |
75 * +----------------------+- - -+--------------------------------+
76 * nlmsg_attrdata(nlh, hdrlen)---^
78 * @par The ACK Netlink Message
79 * This message is actually used to denote both an ACK and a NACK.
80 * Typically, the direction is from FEC to CPC (in response to an ACK
81 * request message). However, the CPC should be able to send ACKs back
82 * to FEC when requested.
85 * 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
86 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
87 * | Netlink message header |
88 * | type = NLMSG_ERROR |
89 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
91 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
92 * | OLD Netlink message header |
93 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
98 * // Various methods exist to create/allocate a new netlink
101 * // nlmsg_alloc() will allocate an empty netlink message with
102 * // a maximum payload size which defaults to the page size of
103 * // the system. This default size can be modified using the
104 * // function nlmsg_set_default_size().
105 * struct nl_msg *msg = nlmsg_alloc();
107 * // Very often, the message type and message flags are known
108 * // at allocation time while the other fields are auto generated:
109 * struct nl_msg *msg = nlmsg_alloc_simple(MY_TYPE, MY_FLAGS);
111 * // Alternatively an existing netlink message header can be used
112 * // to inherit the header values:
113 * struct nlmsghdr hdr = {
114 * .nlmsg_type = MY_TYPE,
115 * .nlmsg_flags = MY_FLAGS,
117 * struct nl_msg *msg = nlmsg_inherit(&hdr);
119 * // Last but not least, netlink messages received from netlink sockets
120 * // can be converted into nl_msg objects using nlmsg_convert(). This
121 * // will create a message with a maximum payload size which equals the
122 * // length of the existing netlink message, therefore no more data can
123 * // be appened without calling nlmsg_expand() first.
124 * struct nl_msg *msg = nlmsg_convert(nlh_from_nl_sock);
126 * // Payload may be added to the message via nlmsg_append(). The fourth
127 * // parameter specifies the number of alignment bytes the data should
128 * // be padding with at the end. Common values are 0 to disable it or
129 * // NLMSG_ALIGNTO to ensure proper netlink message padding.
130 * nlmsg_append(msg, &mydata, sizeof(mydata), 0);
132 * // Sometimes it may be necessary to reserve room for data but defer
133 * // the actual copying to a later point, nlmsg_reserve() can be used
134 * // for this purpose:
135 * void *data = nlmsg_reserve(msg, sizeof(mydata), NLMSG_ALIGNTO);
137 * // Attributes may be added using the attributes interface.
139 * // After successful use of the message, the memory must be freed
140 * // using nlmsg_free()
144 * @par 4) Parsing messages
147 * unsigned char *buf;
148 * struct nlmsghdr *hdr;
150 * n = nl_recv(handle, NULL, &buf);
152 * hdr = (struct nlmsghdr *) buf;
153 * while (nlmsg_ok(hdr, n)) {
154 * // Process message here...
155 * hdr = nlmsg_next(hdr, &n);
161 #include <netlink-local.h>
162 #include <netlink/netlink.h>
163 #include <netlink/utils.h>
164 #include <netlink/cache.h>
165 #include <netlink/attr.h>
166 #include <linux/socket.h>
168 static size_t default_msg_size;
170 static void __init init_msg_size(void)
172 default_msg_size = getpagesize();
176 * @name Size Calculations
181 * length of netlink message not including padding
182 * @arg payload length of message payload
184 int nlmsg_msg_size(int payload)
186 return NLMSG_HDRLEN + payload;
190 * length of netlink message including padding
191 * @arg payload length of message payload
193 int nlmsg_total_size(int payload)
195 return NLMSG_ALIGN(nlmsg_msg_size(payload));
199 * length of padding at the message's tail
200 * @arg payload length of message payload
202 int nlmsg_padlen(int payload)
204 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
210 * @name Payload Access
215 * head of message payload
216 * @arg nlh netlink messsage header
218 void *nlmsg_data(const struct nlmsghdr *nlh)
220 return (unsigned char *) nlh + NLMSG_HDRLEN;
223 void *nlmsg_tail(const struct nlmsghdr *nlh)
225 return (unsigned char *) nlh + NLMSG_ALIGN(nlh->nlmsg_len);
229 * length of message payload
230 * @arg nlh netlink message header
232 int nlmsg_len(const struct nlmsghdr *nlh)
234 return nlh->nlmsg_len - NLMSG_HDRLEN;
240 * @name Attribute Access
245 * head of attributes data
246 * @arg nlh netlink message header
247 * @arg hdrlen length of family specific header
249 struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh, int hdrlen)
251 unsigned char *data = nlmsg_data(nlh);
252 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
256 * length of attributes data
257 * @arg nlh netlink message header
258 * @arg hdrlen length of family specific header
260 int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
262 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
268 * @name Message Parsing
272 int nlmsg_valid_hdr(const struct nlmsghdr *nlh, int hdrlen)
274 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
281 * check if the netlink message fits into the remaining bytes
282 * @arg nlh netlink message header
283 * @arg remaining number of bytes remaining in message stream
285 int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
287 return (remaining >= sizeof(struct nlmsghdr) &&
288 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
289 nlh->nlmsg_len <= remaining);
293 * next netlink message in message stream
294 * @arg nlh netlink message header
295 * @arg remaining number of bytes remaining in message stream
297 * @returns the next netlink message in the message stream and
298 * decrements remaining by the size of the current message.
300 struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
302 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
304 *remaining -= totlen;
306 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
310 * parse attributes of a netlink message
311 * @arg nlh netlink message header
312 * @arg hdrlen length of family specific header
313 * @arg tb destination array with maxtype+1 elements
314 * @arg maxtype maximum attribute type to be expected
315 * @arg policy validation policy
319 int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen, struct nlattr *tb[],
320 int maxtype, struct nla_policy *policy)
322 if (!nlmsg_valid_hdr(nlh, hdrlen))
323 return nl_errno(EINVAL);
325 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
326 nlmsg_attrlen(nlh, hdrlen), policy);
330 * nlmsg_find_attr - find a specific attribute in a netlink message
331 * @arg nlh netlink message header
332 * @arg hdrlen length of familiy specific header
333 * @arg attrtype type of attribute to look for
335 * Returns the first attribute which matches the specified type.
337 struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh, int hdrlen, int attrtype)
339 return nla_find(nlmsg_attrdata(nlh, hdrlen),
340 nlmsg_attrlen(nlh, hdrlen), attrtype);
344 * nlmsg_validate - validate a netlink message including attributes
345 * @arg nlh netlinket message header
346 * @arg hdrlen length of familiy specific header
347 * @arg maxtype maximum attribute type to be expected
348 * @arg policy validation policy
350 int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
351 struct nla_policy *policy)
353 if (!nlmsg_valid_hdr(nlh, hdrlen))
354 return nl_errno(EINVAL);
356 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
357 nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
363 * @name Message Building/Access
367 static struct nl_msg *__nlmsg_alloc(size_t len)
371 nm = calloc(1, sizeof(*nm));
375 nm->nm_nlh = calloc(1, len);
379 nm->nm_protocol = -1;
381 nm->nm_nlh->nlmsg_len = nlmsg_total_size(0);
383 NL_DBG(2, "msg %p: Allocated new message, maxlen=%zu\n", nm, len);
393 * Allocate a new netlink message with the default maximum payload size.
395 * Allocates a new netlink message without any further payload. The
396 * maximum payload size defaults to PAGESIZE or as otherwise specified
397 * with nlmsg_set_default_size().
399 * @return Newly allocated netlink message or NULL.
401 struct nl_msg *nlmsg_alloc(void)
403 return __nlmsg_alloc(default_msg_size);
407 * Allocate a new netlink message with maximum payload size specified.
409 struct nl_msg *nlmsg_alloc_size(size_t max)
411 return __nlmsg_alloc(max);
415 * Allocate a new netlink message and inherit netlink message header
416 * @arg hdr Netlink message header template
418 * Allocates a new netlink message and inherits the original message
419 * header. If \a hdr is not NULL it will be used as a template for
420 * the netlink message header, otherwise the header is left blank.
422 * @return Newly allocated netlink message or NULL
424 struct nl_msg *nlmsg_inherit(struct nlmsghdr *hdr)
430 struct nlmsghdr *new = nm->nm_nlh;
432 new->nlmsg_type = hdr->nlmsg_type;
433 new->nlmsg_flags = hdr->nlmsg_flags;
434 new->nlmsg_seq = hdr->nlmsg_seq;
435 new->nlmsg_pid = hdr->nlmsg_pid;
442 * Allocate a new netlink message
443 * @arg nlmsgtype Netlink message type
444 * @arg flags Message flags.
446 * @return Newly allocated netlink message or NULL.
448 struct nl_msg *nlmsg_alloc_simple(int nlmsgtype, int flags)
451 struct nlmsghdr nlh = {
452 .nlmsg_type = nlmsgtype,
453 .nlmsg_flags = flags,
456 msg = nlmsg_inherit(&nlh);
458 NL_DBG(2, "msg %p: Allocated new simple message\n", msg);
464 * Set the default maximum message payload size for allocated messages
465 * @arg max Size of payload in bytes.
467 void nlmsg_set_default_size(size_t max)
469 if (max < nlmsg_total_size(0))
470 max = nlmsg_total_size(0);
472 default_msg_size = max;
476 * Convert a netlink message received from a netlink socket to a nl_msg
477 * @arg hdr Netlink message received from netlink socket.
479 * Allocates a new netlink message and copies all of the data pointed to
480 * by \a hdr into the new message object.
482 * @return Newly allocated netlink message or NULL.
484 struct nl_msg *nlmsg_convert(struct nlmsghdr *hdr)
488 nm = __nlmsg_alloc(NLMSG_ALIGN(hdr->nlmsg_len));
492 memcpy(nm->nm_nlh, hdr, hdr->nlmsg_len);
501 * Reserve room for additional data in a netlink message
502 * @arg n netlink message
503 * @arg len length of additional data to reserve room for
504 * @arg pad number of bytes to align data to
506 * Reserves room for additional data at the tail of the an
507 * existing netlink message. Eventual padding required will
510 * @return Pointer to start of additional data tailroom or NULL.
512 void *nlmsg_reserve(struct nl_msg *n, size_t len, int pad)
514 void *buf = n->nm_nlh;
515 size_t nlmsg_len = n->nm_nlh->nlmsg_len;
518 tlen = pad ? ((len + (pad - 1)) & ~(pad - 1)) : len;
520 if ((tlen + nlmsg_len) > n->nm_size) {
526 n->nm_nlh->nlmsg_len += tlen;
529 memset(buf + len, 0, tlen - len);
531 NL_DBG(2, "msg %p: Reserved %zu bytes, pad=%d, nlmsg_len=%d\n",
532 n, len, pad, n->nm_nlh->nlmsg_len);
538 * Append data to tail of a netlink message
539 * @arg n netlink message
540 * @arg data data to add
541 * @arg len length of data
542 * @arg pad Number of bytes to align data to.
544 * Extends the netlink message as needed and appends the data of given
545 * length to the message.
547 * @return 0 on success or a negative error code
549 int nlmsg_append(struct nl_msg *n, void *data, size_t len, int pad)
553 tmp = nlmsg_reserve(n, len, pad);
555 return nl_errno(ENOMEM);
557 memcpy(tmp, data, len);
558 NL_DBG(2, "msg %p: Appended %zu bytes with padding %d\n", n, len, pad);
564 * Expand maximum payload size of a netlink message
565 * @arg n Netlink message.
566 * @arg newlen New maximum payload size.
568 * Reallocates the payload section of a netlink message and increases
569 * the maximum payload size of the message.
571 * @note Any pointers pointing to old payload block will be stale and
572 * need to be refetched. Therfore, do not expand while constructing
573 * nested attributes or while reserved data blocks are held.
575 * @return 0 on success or a negative error code.
577 int nlmsg_expand(struct nl_msg *n, size_t newlen)
581 if (newlen <= n->nm_size)
582 return nl_errno(EINVAL);
584 tmp = realloc(n->nm_nlh, newlen);
586 return nl_errno(ENOMEM);
595 * Add a netlink message header to a netlink message
596 * @arg n netlink message
597 * @arg pid netlink process id or NL_AUTO_PID
598 * @arg seq sequence number of message or NL_AUTO_SEQ
599 * @arg type message type
600 * @arg payload length of message payload
601 * @arg flags message flags
603 * Adds or overwrites the netlink message header in an existing message
604 * object. If \a payload is greater-than zero additional room will be
605 * reserved, f.e. for family specific headers. It can be accesed via
608 * @return A pointer to the netlink message header or NULL.
610 struct nlmsghdr *nlmsg_put(struct nl_msg *n, uint32_t pid, uint32_t seq,
611 int type, int payload, int flags)
613 struct nlmsghdr *nlh;
615 if (n->nm_nlh->nlmsg_len < NLMSG_HDRLEN)
618 nlh = (struct nlmsghdr *) n->nm_nlh;
619 nlh->nlmsg_type = type;
620 nlh->nlmsg_flags = flags;
621 nlh->nlmsg_pid = pid;
622 nlh->nlmsg_seq = seq;
624 NL_DBG(2, "msg %p: Added netlink header type=%d, flags=%d, pid=%d, "
625 "seq=%d\n", n, type, flags, pid, seq);
628 nlmsg_reserve(n, payload, NLMSG_ALIGNTO) == NULL)
635 * Return actual netlink message
636 * @arg n netlink message
638 * Returns the actual netlink message casted to the type of the netlink
641 * @return A pointer to the netlink message.
643 struct nlmsghdr *nlmsg_hdr(struct nl_msg *n)
649 * Free a netlink message
650 * @arg n netlink message
652 * Destroys a netlink message and frees up all used memory.
654 * @pre The message must be unused.
656 void nlmsg_free(struct nl_msg *n)
663 NL_DBG(2, "msg %p: Freed\n", n);
673 void nlmsg_set_proto(struct nl_msg *msg, int protocol)
675 msg->nm_protocol = protocol;
678 int nlmsg_get_proto(struct nl_msg *msg)
680 return msg->nm_protocol;
683 size_t nlmsg_get_max_size(struct nl_msg *msg)
688 void nlmsg_set_src(struct nl_msg *msg, struct sockaddr_nl *addr)
690 memcpy(&msg->nm_src, addr, sizeof(*addr));
693 struct sockaddr_nl *nlmsg_get_src(struct nl_msg *msg)
698 void nlmsg_set_dst(struct nl_msg *msg, struct sockaddr_nl *addr)
700 memcpy(&msg->nm_dst, addr, sizeof(*addr));
703 struct sockaddr_nl *nlmsg_get_dst(struct nl_msg *msg)
708 void nlmsg_set_creds(struct nl_msg *msg, struct ucred *creds)
710 memcpy(&msg->nm_creds, creds, sizeof(*creds));
711 msg->nm_flags |= NL_MSG_CRED_PRESENT;
714 struct ucred *nlmsg_get_creds(struct nl_msg *msg)
716 if (msg->nm_flags & NL_MSG_CRED_PRESENT)
717 return &msg->nm_creds;
724 * @name Netlink Message Type Translations
728 static struct trans_tbl nl_msgtypes[] = {
729 __ADD(NLMSG_NOOP,NOOP)
730 __ADD(NLMSG_ERROR,ERROR)
731 __ADD(NLMSG_DONE,DONE)
732 __ADD(NLMSG_OVERRUN,OVERRUN)
735 char *nl_nlmsgtype2str(int type, char *buf, size_t size)
737 return __type2str(type, buf, size, nl_msgtypes,
738 ARRAY_SIZE(nl_msgtypes));
741 int nl_str2nlmsgtype(const char *name)
743 return __str2type(name, nl_msgtypes, ARRAY_SIZE(nl_msgtypes));
749 * @name Netlink Message Flags Translations
753 char *nl_nlmsg_flags2str(int flags, char *buf, size_t len)
757 #define PRINT_FLAG(f) \
758 if (flags & NLM_F_##f) { \
759 flags &= ~NLM_F_##f; \
760 strncat(buf, #f, len - strlen(buf) - 1); \
762 strncat(buf, ",", len - strlen(buf) - 1); \
779 snprintf(s, sizeof(s), "0x%x", flags);
780 strncat(buf, s, len - strlen(buf) - 1);
790 * @name Direct Parsing
796 void (*cb)(struct nl_object *, void *);
801 static int parse_cb(struct nl_object *obj, struct nl_parser_param *p)
803 struct dp_xdata *x = p->pp_arg;
809 int nl_msg_parse(struct nl_msg *msg, void (*cb)(struct nl_object *, void *),
812 struct nl_cache_ops *ops;
813 struct nl_parser_param p = {
816 struct dp_xdata x = {
821 ops = nl_cache_ops_associate(nlmsg_get_proto(msg),
822 nlmsg_hdr(msg)->nlmsg_type);
824 return nl_error(ENOENT, "Unknown message type %d",
825 nlmsg_hdr(msg)->nlmsg_type);
828 return nl_cache_parse(ops, NULL, nlmsg_hdr(msg), &p);
838 static void prefix_line(FILE *ofd, int prefix)
842 for (i = 0; i < prefix; i++)
846 static inline void dump_hex(FILE *ofd, char *start, int len, int prefix)
849 char ascii[21] = {0};
851 limit = 18 - (prefix * 2);
852 prefix_line(ofd, prefix);
855 for (i = 0, a = 0, c = 0; i < len; i++) {
856 int v = *(uint8_t *) (start + i);
858 fprintf(ofd, "%02x ", v);
859 ascii[a++] = isprint(v) ? v : '.';
862 fprintf(ofd, "%s\n", ascii);
864 prefix_line(ofd, prefix);
868 memset(ascii, 0, sizeof(ascii));
874 for (i = 0; i < (limit - c); i++)
876 fprintf(ofd, "%s\n", ascii);
880 static void print_hdr(FILE *ofd, struct nl_msg *msg)
882 struct nlmsghdr *nlh = nlmsg_hdr(msg);
883 struct nl_cache_ops *ops;
884 struct nl_msgtype *mt;
887 fprintf(ofd, " .nlmsg_len = %d\n", nlh->nlmsg_len);
889 ops = nl_cache_ops_associate(nlmsg_get_proto(msg), nlh->nlmsg_type);
891 mt = nl_msgtype_lookup(ops, nlh->nlmsg_type);
895 snprintf(buf, sizeof(buf), "%s::%s", ops->co_name, mt->mt_name);
897 nl_nlmsgtype2str(nlh->nlmsg_type, buf, sizeof(buf));
899 fprintf(ofd, " .nlmsg_type = %d <%s>\n", nlh->nlmsg_type, buf);
900 fprintf(ofd, " .nlmsg_flags = %d <%s>\n", nlh->nlmsg_flags,
901 nl_nlmsg_flags2str(nlh->nlmsg_flags, buf, sizeof(buf)));
902 fprintf(ofd, " .nlmsg_seq = %d\n", nlh->nlmsg_seq);
903 fprintf(ofd, " .nlmsg_pid = %d\n", nlh->nlmsg_pid);
907 static void dump_attrs(FILE *ofd, struct nlattr *attrs, int attrlen,
913 nla_for_each_attr(nla, attrs, attrlen, rem) {
914 int padlen, alen = nla_len(nla);
916 prefix_line(ofd, prefix);
917 fprintf(ofd, " [ATTR %02d%s] %d octets\n", nla_type(nla),
918 nla->nla_type & NLA_F_NESTED ? " NESTED" : "",
921 if (nla->nla_type & NLA_F_NESTED)
922 dump_attrs(ofd, nla_data(nla), alen, prefix+1);
924 dump_hex(ofd, nla_data(nla), alen, prefix);
926 padlen = nla_padlen(alen);
928 prefix_line(ofd, prefix);
929 fprintf(ofd, " [PADDING] %d octets\n",
931 dump_hex(ofd, nla_data(nla) + alen,
937 prefix_line(ofd, prefix);
938 fprintf(ofd, " [LEFTOVER] %d octets\n", rem);
943 * Dump message in human readable format to file descriptor
944 * @arg msg Message to print
945 * @arg ofd File descriptor.
947 void nl_msg_dump(struct nl_msg *msg, FILE *ofd)
949 struct nlmsghdr *hdr = nlmsg_hdr(msg);
952 "-------------------------- BEGIN NETLINK MESSAGE "
953 "---------------------------\n");
955 fprintf(ofd, " [HEADER] %Zu octets\n", sizeof(struct nlmsghdr));
958 if (hdr->nlmsg_type == NLMSG_ERROR &&
959 hdr->nlmsg_len >= nlmsg_msg_size(sizeof(struct nlmsgerr))) {
960 struct nl_msg *errmsg;
961 struct nlmsgerr *err = nlmsg_data(hdr);
963 fprintf(ofd, " [ERRORMSG] %Zu octets\n", sizeof(*err));
964 fprintf(ofd, " .error = %d \"%s\"\n", err->error,
965 strerror(-err->error));
966 fprintf(ofd, " [ORIGINAL MESSAGE] %Zu octets\n", sizeof(*hdr));
968 errmsg = nlmsg_inherit(&err->msg);
969 print_hdr(ofd, errmsg);
971 } else if (nlmsg_len(hdr) > 0) {
972 struct nl_cache_ops *ops;
973 int payloadlen = nlmsg_len(hdr);
976 ops = nl_cache_ops_associate(nlmsg_get_proto(msg),
979 attrlen = nlmsg_attrlen(hdr, ops->co_hdrsize);
980 payloadlen -= attrlen;
983 fprintf(ofd, " [PAYLOAD] %d octets\n", payloadlen);
984 dump_hex(ofd, nlmsg_data(hdr), payloadlen, 0);
987 struct nlattr *attrs;
990 attrs = nlmsg_attrdata(hdr, ops->co_hdrsize);
991 attrlen = nlmsg_attrlen(hdr, ops->co_hdrsize);
992 dump_attrs(ofd, attrs, attrlen, 0);
997 "--------------------------- END NETLINK MESSAGE "
998 "---------------------------\n");