4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * All rights reserved. This program and the accompanying materials
7 * are made available under the terms of the GNU Lesser General Public License
8 * LGPL version 2.1 or (at your discretion) any later version.
9 * LGPL version 2.1 accompanies this distribution, and is available at
10 * http://www.gnu.org/licenses/lgpl-2.1.html
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
22 * Copyright (c) 2021 UT-Battelle, LLC
24 * Author: James Simmons <jsimmons@infradead.org>
32 #include <linux/lnet/lnet-nl.h>
33 #include "liblnetconfig.h"
35 #ifndef SOL_NETLINK /* for glibc < 2.24 */
36 # define SOL_NETLINK 270
39 #ifndef NETLINK_EXT_ACK
40 #define NETLINK_EXT_ACK 11
43 #ifndef NLM_F_ACK_TLVS
44 #define NLM_F_ACK_TLVS 0x200 /* extended ACK TVLs were included */
47 #ifndef NLA_NUL_STRING
48 # define NLA_NUL_STRING 10
55 #ifndef HAVE_NLA_GET_S32
60 * Return payload of 32 bit signed integer attribute.
62 * @arg nla 32 bit integer attribute.
64 * @return Payload as 32 bit integer.
66 int32_t nla_get_s32(const struct nlattr *nla)
68 return *(const int32_t *) nla_data(nla);
70 #endif /* ! HAVE_NLA_GET_S32 */
72 #ifndef HAVE_NLA_GET_S64
77 * Return payload of s64 attribute
79 * @arg nla s64 netlink attribute
81 * @return Payload as 64 bit integer.
83 int64_t nla_get_s64(const struct nlattr *nla)
87 if (nla && nla_len(nla) >= sizeof(tmp))
88 memcpy(&tmp, nla_data(nla), sizeof(tmp));
93 #define NLA_PUT_S64(msg, attrtype, value) \
94 NLA_PUT_TYPE(msg, int64_t, attrtype, value)
96 #endif /* ! HAVE_NLA_GET_S64 */
99 * Set NETLINK_BROADCAST_ERROR flags on socket to report ENOBUFS errors.
101 * @sk Socket to change the flags.
103 * Return 0 on success or a Netlink error code.
105 int nl_socket_enable_broadcast_error(struct nl_sock *sk)
107 const int state = 1; /* enable errors */
110 if (nl_socket_get_fd(sk) < 0)
111 return -NLE_BAD_SOCK;
113 err = setsockopt(nl_socket_get_fd(sk), SOL_NETLINK,
114 NETLINK_BROADCAST_ERROR, &state, sizeof(state));
116 return -nl_syserr2nlerr(errno);
122 * Enable/disable extending ACK for netlink socket. Used for
123 * sending extra debugging information.
125 * @arg sk Netlink socket.
126 * @arg state New state (0 - disabled, 1 - enabled)
128 * @return 0 on success or a negative error code
130 int nl_socket_set_ext_ack(struct nl_sock *sk, int state)
134 if (nl_socket_get_fd(sk) < 0)
135 return -NLE_BAD_SOCK;
137 err = setsockopt(nl_socket_get_fd(sk), SOL_NETLINK,
138 NETLINK_EXT_ACK, &state, sizeof(state));
139 if (err < 0 && errno != ENOPROTOOPT)
140 return -nl_syserr2nlerr(errno);
146 * Create a Netlink socket
148 * @sk The nl_sock which we used to handle the Netlink
150 * @async_events tell the Netlink socket this will receive asynchronous
153 * Return 0 on success or a negative error code.
155 int lustre_netlink_register(struct nl_sock *sk, bool async_events)
159 rc = genl_connect(sk);
163 rc = nl_socket_enable_broadcast_error(sk);
167 rc = nl_socket_set_ext_ack(sk, true);
172 /* Required to receive async netlink event notifications */
173 nl_socket_disable_seq_check(sk);
174 /* Don't need ACK for events generated by kernel */
175 nl_socket_disable_auto_ack(sk);
182 * Filter Netlink socket by groups
185 * @family The family name of the Netlink socket.
186 * @group Netlink messages will only been sent if they belong to this
189 * Return 0 on success or a negative error code.
191 int lustre_netlink_add_group(struct nl_sock *nl, const char *family,
197 group_id = genl_ctrl_resolve_grp(nl, family, group);
201 /* subscribe to generic netlink multicast group */
202 return nl_socket_add_membership(nl, group_id);
205 /* A YAML file is used to describe data. In a YAML document the content is
206 * all about a collection of scalars used to create new data types such as
207 * key-value pairs. This allows complex documents to represent anything from
208 * a string to a tree.
212 * YAML scalars are a simple value which can be a string, number or Boolean.
213 * They are the simplest data types. They can exist in a YAML document but
214 * are typically used to build more complex data formats.
218 * In YAML collections are scalar elements presented in the form of
219 * an array, called a sequence, or mappings (hashes) that are scalar
220 * key value pairs. All elements belonging to the same collection are
221 * the lines that begin at the same indentation level
223 * Sequences use a dash followed by a space.
224 * Mappings use a colon followed by a space (: ) to mark each key/value pair:
226 * Collections can be represented in two forms, flow and block.
227 * Note they are equivalent. Example of block sequence is;
233 * and a block mapping example is:
239 * YAML flow styles for collections uses explicit indicators rather than
240 * indentation to denote scope.
242 * A sequence can be written as a comma separated list within
243 * square brackets ([]):
245 * [ PHP, Perl, Python ]
247 * A mapping can be written as a comma separated list of key/values within
250 * { PHP: 5.2, MySQL: 5.1, Apache: 2.2.20 }
252 * NOTE!! flow and block are equivalent.
256 * A list is a defined array of data which can be either an flow or block
257 * sequence. Lists can be nested. Example
259 * numbers: [ 1, 2, 3, 4 ]
269 * Are comprised of a key: value format with contents indented. This is
270 * built on top of the flow or block mapping. Like lists they can be nested.
278 /* In YAML you have the concept of parsers and emitters. Parser
279 * consume YAML input from a file, character buffer, or in our
280 * case Netlink and emitters take data from some source and
281 * present it in a YAML format.
283 * In this section of the code we are handling the parsing of the
284 * Netlink packets coming in and using them to piece together a
285 * YAML document. We could in theory just dump a YAML document
286 * one line at a time over Netlink but the amount of data could
287 * become very large and impact performance. Additionally, having
288 * pseudo-YAML code in the kernel would be frowned on. We can
289 * optimize the network traffic by taking advantage of the fact
290 * that for key/value pairs the keys rarely change. We can
291 * break up the data into keys and the values. The first Netlink
292 * data packets received will be a nested keys table which we
293 * can cache locally. As we receive the value pairs we can then
294 * reconstruct the key : value pair by looking up the the key
295 * in the stored table. In effect we end up with a one key to
296 * many values stream of data.
298 * The data structures below are used to create a tree data
299 * structure which is the natural flow of both YAML and
302 struct yaml_nl_node {
303 struct nl_list_head list;
304 struct nl_list_head children;
305 struct ln_key_list keys;
308 struct yaml_netlink_input {
309 yaml_parser_t *parser;
316 struct yaml_nl_node *cur;
317 struct yaml_nl_node *root;
320 /* Sadly this is not exported out of libyaml. We want to
321 * give descent error message to help people track down
322 * issues. This is internal only to this code. The end
323 * user will never need to use this.
326 yaml_parser_set_reader_error(yaml_parser_t *parser, const char *problem,
327 size_t offset, int value)
329 parser->error = YAML_READER_ERROR;
330 parser->problem = problem;
331 parser->problem_offset = offset;
332 parser->problem_value = value;
337 /* This is used to handle all the Netlink packets containing the keys
338 * for the key/value pairs. Instead of creating unique code to handle
339 * every type of Netlink attributes possible we create a generic
340 * abstract so the same code be used with everything. To make this
341 * work the key table trasmitted must report the tree structure and
342 * state of the keys. We use nested attributes as a way to notify libyaml
343 * we have a new collection. This is used to create the tree structure
344 * of the YAML document. Each collection of attributes define the following:
346 * LN_SCALAR_ATTR_INDEX:
347 * enum XXX_ATTR that defines which value we are dealing with. This
348 * varies greatly depending on the subsystem we have developed for.
350 * LN_SCALAR_ATTR_NLA_TYPE:
351 * The Netlink attribute type (NLA_STRING, NLA_U32, etc..) the coming
354 * LN_SCALAR_ATTR_VALUE:
355 * The string represnting key's actually scalar value.
357 * LN_SCALAR_ATTR_INT_VALUE:
358 * For this case the key is an integer value. This shouldn't be
359 * sent for the receive case since we are going to just turn it
360 * into a string for YAML. Sending packets will make use of this.
362 * LN_SCALAR_ATTR_KEY_TYPE:
363 * What YAML format is it? block or flow. Only useful for
364 * LN_SCALAR_ATTR_NLA_TYPE of type NLA_NESTED or NLA_NUL_STRING
366 * LN_SCALAR_ATTR_LIST + LN_SCALAR_LIST_SIZE:
367 * Defined the next collection which is a collection of nested
368 * attributes of the above.
370 static struct nla_policy scalar_attr_policy[LN_SCALAR_MAX + 1] = {
371 [LN_SCALAR_ATTR_LIST] = { .type = NLA_NESTED },
372 [LN_SCALAR_ATTR_LIST_SIZE] = { .type = NLA_U16 },
373 [LN_SCALAR_ATTR_INDEX] = { .type = NLA_U16 },
374 [LN_SCALAR_ATTR_NLA_TYPE] = { .type = NLA_U16 },
375 [LN_SCALAR_ATTR_VALUE] = { .type = NLA_STRING },
376 [LN_SCALAR_ATTR_INT_VALUE] = { .type = NLA_S64 },
377 [LN_SCALAR_ATTR_KEY_FORMAT] = { .type = NLA_U16 },
380 static int yaml_parse_key_list(struct yaml_netlink_input *data,
381 struct yaml_nl_node *parent,
384 struct nlattr *tbl_info[LN_SCALAR_MAX + 1];
385 struct yaml_nl_node *node = NULL;
389 nla_for_each_nested(attr, list, rem) {
392 if (nla_parse_nested(tbl_info, LN_SCALAR_MAX, attr,
396 if (tbl_info[LN_SCALAR_ATTR_LIST_SIZE]) {
399 cnt = nla_get_u16(tbl_info[LN_SCALAR_ATTR_LIST_SIZE]) + 1;
401 size_t len = sizeof(struct nl_list_head) * 2;
403 len += sizeof(struct ln_key_props) * cnt;
404 node = calloc(1, len);
408 node->keys.lkl_maxattr = cnt;
409 NL_INIT_LIST_HEAD(&node->children);
410 nl_init_list_head(&node->list);
417 nl_list_add_tail(&node->list,
422 if (tbl_info[LN_SCALAR_ATTR_INDEX])
423 index = nla_get_u16(tbl_info[LN_SCALAR_ATTR_INDEX]);
425 if (!node || index == 0)
428 if (tbl_info[LN_SCALAR_ATTR_KEY_FORMAT]) {
431 format = nla_get_u16(tbl_info[LN_SCALAR_ATTR_KEY_FORMAT]);
432 node->keys.lkl_list[index].lkp_key_format = format;
435 if (tbl_info[LN_SCALAR_ATTR_NLA_TYPE]) {
438 type = nla_get_u16(tbl_info[LN_SCALAR_ATTR_NLA_TYPE]);
439 node->keys.lkl_list[index].lkp_data_type = type;
442 if (tbl_info[LN_SCALAR_ATTR_VALUE]) {
445 name = nla_strdup(tbl_info[LN_SCALAR_ATTR_VALUE]);
448 node->keys.lkl_list[index].lkp_value = name;
451 if (tbl_info[LN_SCALAR_ATTR_LIST]) {
452 int rc = yaml_parse_key_list(data, node,
453 tbl_info[LN_SCALAR_ATTR_LIST]);
461 static struct yaml_nl_node *get_next_child(struct yaml_nl_node *node,
464 struct yaml_nl_node *child;
467 nl_list_for_each_entry(child, &node->children, list)
475 * In the YAML C implementation the scanner transforms the input stream
476 * (Netlink in this case) into a sequence of keys. First we need to
477 * examine the potential keys involved to see the mapping to Netlink.
478 * We have chosen to examine the YAML stack with keys since they are
479 * more detailed when compared to yaml_document_t / yaml_nodes and
482 * STREAM-START(encoding) # The stream start.
483 * STREAM-END # The stream end.
484 * VERSION-DIRECTIVE(major,minor) # The '%YAML' directive.
485 * TAG-DIRECTIVE(handle,prefix) # The '%TAG' directive.
486 * DOCUMENT-START # '---'
487 * DOCUMENT-END # '...'
488 * BLOCK-SEQUENCE-START # Indentation increase denoting a block
489 * BLOCK-MAPPING-START # sequence or a block mapping.
490 * BLOCK-END # Indentation decrease.
491 * FLOW-SEQUENCE-START # '['
492 * FLOW-SEQUENCE-END # ']'
493 * FLOW-MAPPING-START # '{'
494 * FLOW-MAPPING-END # '}'
497 * KEY # '?' or nothing (simple keys).
499 * ALIAS(anchor) # '*anchor'
500 * ANCHOR(anchor) # '&anchor'
501 * TAG(handle,suffix) # '!handle!suffix'
502 * SCALAR(value,style) # A scalar.
504 * For our read_handler / write_handler STREAM-START / STREAM-END,
505 * VERSION-DIRECTIVE, and TAG-DIRECTIVE are hanndler by the libyaml
506 * internal scanner so we don't need to deal with it. Normally for
507 * LNet / Lustre DOCUMENT-START / DOCUMENT-END are not needed but it
508 * could be easily handled. In the case of multiplex streams we could
509 * see these used to differentiate data coming in.
511 * It is here we handle any simple scalars or values of the key /value
512 * pair. How the YAML document is formated is dependent on the key
515 static void yaml_parse_value_list(struct yaml_netlink_input *data, int *size,
516 struct nlattr *attr_array[],
517 struct ln_key_props *parent)
519 struct yaml_nl_node *node = data->cur;
520 struct ln_key_props *keys = node->keys.lkl_list;
521 int mapping = parent->lkp_key_format;
522 int child_idx = 0, len = 0, i;
524 for (i = 1; i < node->keys.lkl_maxattr; i++) {
527 attr = attr_array[i];
528 if (!attr && !keys[i].lkp_value)
531 if (keys[i].lkp_data_type != NLA_NUL_STRING &&
532 keys[i].lkp_data_type != NLA_NESTED) {
536 if (!(mapping & LNKF_FLOW)) {
537 unsigned int indent = data->indent ?
540 memset(data->buffer, ' ', indent);
541 if (mapping & LNKF_SEQUENCE) {
542 ((char *)data->buffer)[indent - 2] = '-';
543 if (mapping & LNKF_MAPPING)
544 mapping &= ~LNKF_SEQUENCE;
546 data->buffer += indent;
550 if (mapping & LNKF_MAPPING) {
551 len = snprintf(data->buffer, *size, "%s: ",
560 switch (keys[i].lkp_data_type) {
562 struct yaml_nl_node *next = get_next_child(node,
564 int num = next->keys.lkl_maxattr;
565 struct nla_policy nest_policy[num];
566 struct yaml_nl_node *old;
567 struct nlattr *cnt_attr;
573 memset(nest_policy, 0, sizeof(struct nla_policy) * num);
574 for (j = 1; j < num; j++)
575 nest_policy[j].type = next->keys.lkl_list[j].lkp_data_type;
579 nla_for_each_nested(cnt_attr, attr, rem) {
580 struct nlattr *nest_info[num];
583 if (nla_parse_nested(nest_info, num, cnt_attr,
587 if (keys[i].lkp_key_format & LNKF_FLOW) {
590 if (keys[i].lkp_key_format &
594 len = snprintf(data->buffer, *size,
600 if (keys[i].lkp_key_format &
603 if (keys[i].lkp_key_format &
607 len = snprintf(data->buffer, *size,
618 data->indent += indent;
619 yaml_parse_value_list(data, size, nest_info,
621 data->indent -= indent;
623 if (keys[i].lkp_key_format & LNKF_FLOW) {
624 char *tmp = (char *)data->buffer - 2;
625 char *brace = " }\n";
627 if (keys[i].lkp_key_format &
631 memcpy(tmp, brace, strlen(brace));
642 if (data->cur != data->root)
645 /* The top level is special so only print
648 if (strlen(keys[i].lkp_value)) {
649 len = snprintf(data->buffer,
659 if (!(mapping & LNKF_FLOW)) {
660 if (mapping & LNKF_SEQUENCE)
662 else if (mapping & LNKF_MAPPING)
666 if (attr && parent->lkp_value) {
667 free(parent->lkp_value);
668 parent->lkp_value = nla_strdup(attr);
674 len = snprintf(data->buffer, *size, "%s",
675 nla_get_string(attr));
679 len = snprintf(data->buffer, *size, "%hu",
684 len = snprintf(data->buffer, *size, "%u",
689 len = snprintf(data->buffer, *size, "%ju",
694 len = snprintf(data->buffer, *size, "%hd",
699 len = snprintf(data->buffer, *size, "%d",
704 len = snprintf(data->buffer, *size, "%jd",
712 if (mapping & LNKF_FLOW) {
713 strcat((char *)data->buffer, ", ");
716 ((char *)data->buffer)[len++] = '\n';
720 } else if (len < 0) {
722 data->buffer -= data->indent + 2;
723 *size -= data->indent + 2;
728 /* This is the CB_VALID callback for the Netlink library that we
729 * have hooked into. Any successful Netlink message is passed to
730 * this function which handles both the incoming key tables and
731 * the values of the key/value pairs being received. We use
732 * the NLM_F_CREATE flag to determine if the incoming Netlink
733 * message is a key table or a packet containing value pairs.
735 static int yaml_netlink_msg_parse(struct nl_msg *msg, void *arg)
737 struct yaml_netlink_input *data = arg;
738 struct nlmsghdr *nlh = nlmsg_hdr(msg);
740 if (nlh->nlmsg_flags & NLM_F_CREATE) {
741 struct nlattr *attrs[LN_SCALAR_MAX + 1];
743 if (genlmsg_parse(nlh, 0, attrs, LN_SCALAR_MAX + 1,
747 if (attrs[LN_SCALAR_ATTR_LIST]) {
748 int rc = yaml_parse_key_list(data, NULL,
749 attrs[LN_SCALAR_ATTR_LIST]);
753 /* reset to root node */
754 data->cur = data->root;
757 /* For streaming insert '---' to define start of
758 * YAML document. This allows use to extract
759 * documents out of a multiplexed stream.
762 char *start_doc = "---\n";
763 size_t len = strlen(start_doc) + 1;
765 strncpy(data->buffer, start_doc, len);
766 data->buffer += len - 1;
769 uint16_t maxtype = data->cur->keys.lkl_maxattr;
770 struct nla_policy policy[maxtype];
771 struct nlattr *attrs[maxtype];
774 memset(policy, 0, sizeof(struct nla_policy) * maxtype);
775 for (i = 1; i < maxtype; i++)
776 policy[i].type = data->cur->keys.lkl_list[i].lkp_data_type;
778 if (genlmsg_parse(nlh, 0, attrs, maxtype, policy))
781 size = data->parser->raw_buffer.end -
782 (unsigned char *)data->buffer;
783 yaml_parse_value_list(data, &size, attrs,
784 &data->cur->keys.lkl_list[1]);
787 /* Let yaml_netlink_msg_complete end collecting data */
791 static bool cleanup_children(struct yaml_nl_node *parent)
793 struct yaml_nl_node *child;
795 if (nl_list_empty(&parent->children)) {
796 struct ln_key_props *keys = parent->keys.lkl_list;
799 for (i = 1; i < parent->keys.lkl_maxattr; i++)
800 if (keys[i].lkp_value)
801 free(keys[i].lkp_value);
802 nl_list_del(&parent->list);
806 while ((child = get_next_child(parent, 0)) != NULL) {
807 if (cleanup_children(child))
814 /* This is the libnl callback for when the last Netlink packet
815 * is finished being parsed or its called right away in case
816 * the Linux kernel reports back an error from the Netlink layer.
818 static int yaml_netlink_msg_complete(struct nl_msg *msg, void *arg)
820 struct yaml_netlink_input *data = arg;
821 struct nlmsghdr *nlh = nlmsg_hdr(msg);
822 struct nlmsgerr *errmsg = nlmsg_data(nlh);
824 if ((nlh->nlmsg_type == NLMSG_ERROR ||
825 nlh->nlmsg_flags & NLM_F_ACK_TLVS) && errmsg->error) {
826 /* libyaml stomps on the reader error so we need to
827 * cache the source of the error.
829 data->errmsg = nl_geterror(nl_syserr2nlerr(errmsg->error));
830 #ifdef HAVE_USRSPC_NLMSGERR
831 /* Newer kernels support NLM_F_ACK_TLVS in nlmsg_flags
832 * which gives greater detail why we failed.
834 if (nlh->nlmsg_flags & NLM_F_ACK_TLVS &&
835 !(nlh->nlmsg_flags & NLM_F_CAPPED)) {
836 struct nlattr *head = ((void *)&errmsg->msg);
837 struct nlattr *tb[NLMSGERR_ATTR_MAX + 1];
839 if (nla_parse(tb, NLMSGERR_ATTR_MAX + 1, head,
840 nlmsg_attrlen(nlh, 0), NULL) == 0) {
841 if (tb[NLMSGERR_ATTR_MSG])
842 data->errmsg = nla_strdup(tb[NLMSGERR_ATTR_MSG]);
845 #endif /* HAVE_USRSPC_NLMSGERR */
846 data->parser->error = YAML_READER_ERROR;
847 data->complete = true;
852 cleanup_children(data->root);
856 /* For streaming insert '...' to define end of
860 char *end_doc = "...\n";
861 size_t len = strlen(end_doc) + 1;
863 strncpy(data->buffer, end_doc, len);
864 data->buffer += len - 1;
866 data->complete = true;
869 return data->async ? NL_OK : NL_STOP;
873 * In order for yaml_parser_set_input_netlink() to work we have to
874 * register a yaml_read_handler_t callback. This is that call back
875 * which listens for Netlink packets. Internally nl_recvmsg_report()
876 * calls the various callbacks discussed above.
878 static int yaml_netlink_read_handler(void *arg, unsigned char *buffer,
879 size_t size, size_t *size_read)
881 struct yaml_netlink_input *data = arg;
882 struct nl_sock *nl = data->nl;
886 if (data->complete) {
891 data->buffer = buffer;
893 cb = nl_socket_get_cb(nl);
894 rc = nl_recvmsgs_report(nl, cb);
895 if (rc == -NLE_INTR) {
899 data->errmsg = nl_geterror(rc);
901 } else if (data->parser->error) {
902 /* data->errmsg is set in NL_CB_FINISH */
906 rc = (unsigned char *)data->buffer - buffer;
914 /* libyaml by default just reports "input error" for parser read_handler_t
915 * issues which is not useful. This provides away to get better debugging
918 YAML_DECLARE(const char *)
919 yaml_parser_get_reader_error(yaml_parser_t *parser)
921 struct yaml_netlink_input *buf = parser->read_handler_data;
929 /* yaml_parser_set_input_netlink() mirrors the libyaml function
930 * yaml_parser_set_input_file(). Internally it does setup of the
931 * libnl socket callbacks to parse the Netlink messages received
932 * as well as register the special yaml_read_handler_t for libyaml.
933 * This is exposed for public use.
936 yaml_parser_set_input_netlink(yaml_parser_t *reply, struct nl_sock *nl,
939 struct yaml_netlink_input *buf;
942 buf = calloc(1, sizeof(*buf));
944 reply->error = YAML_MEMORY_ERROR;
948 rc = lustre_netlink_register(nl, stream);
950 yaml_parser_set_reader_error(reply,
951 "netlink setup failed", 0,
959 yaml_parser_set_input(buf->parser, yaml_netlink_read_handler, buf);
961 rc = nl_socket_modify_cb(buf->nl, NL_CB_VALID, NL_CB_CUSTOM,
962 yaml_netlink_msg_parse, buf);
964 yaml_parser_set_reader_error(reply,
965 "netlink msg recv setup failed",
970 rc = nl_socket_modify_cb(buf->nl, NL_CB_FINISH, NL_CB_CUSTOM,
971 yaml_netlink_msg_complete, buf);
973 yaml_parser_set_reader_error(reply,
974 "netlink msg cleanup setup failed",
979 return rc < 0 ? false : true;
982 /* The role of the YAML emitter for us is to take a YAML document and
983 * change into a Netlink stream to send to the kernel to be processed.
984 * This provides the infrastructure to do this.
986 struct yaml_netlink_output {
987 yaml_emitter_t *emitter;
997 /* Internal use for this file only. We fill in details of why creating
998 * a Netlink packet to send failed. The end user will be able to debug
1002 yaml_emitter_set_writer_error(yaml_emitter_t *emitter, const char *problem)
1004 emitter->error = YAML_WRITER_ERROR;
1005 emitter->problem = problem;
1010 static unsigned int indent_level(const char *str)
1012 char *tmp = (char *)str;
1014 while (isspace(*tmp))
1021 static enum lnet_nl_key_format yaml_format_type(yaml_emitter_t *emitter,
1023 unsigned int *offset,
1024 enum lnet_nl_key_format prev)
1026 enum lnet_nl_key_format fmt = 0;
1027 unsigned int indent = *offset;
1028 unsigned int new_indent = 0;
1030 if (strchr(line, '{') || strchr(line, '[')) {
1032 if (strchr(line, '{'))
1033 fmt |= LNKF_MAPPING;
1037 new_indent = indent_level(line);
1038 if (new_indent < indent) {
1039 *offset = indent - emitter->best_indent;
1043 if (strncmp(line + new_indent, "- ", 2) == 0) {
1044 *offset = new_indent + emitter->best_indent;
1045 fmt = LNKF_SEQUENCE;
1047 if (strstr(line + new_indent, ": "))
1048 fmt |= LNKF_MAPPING;
1052 if (indent != new_indent) {
1053 *offset = new_indent;
1054 if (prev != LNKF_MAPPING)
1055 return LNKF_MAPPING;
1061 static int yaml_fill_scalar_data(struct nl_msg *msg,
1062 enum lnet_nl_key_format fmt,
1065 char *sep = strchr(line, ':');
1071 NLA_PUT_STRING(msg, LN_SCALAR_ATTR_VALUE, line);
1072 if (fmt & LNKF_MAPPING && sep) {
1073 while (isspace(*sep))
1076 if (strspn(sep, "0123456789") == strlen(sep)) {
1077 unsigned long num = strtoull(sep, NULL, 0);
1079 NLA_PUT_S64(msg, LN_SCALAR_ATTR_INT_VALUE, num);
1081 NLA_PUT_STRING(msg, LN_SCALAR_ATTR_VALUE, sep);
1088 static int yaml_create_nested_list(struct yaml_netlink_output *out,
1089 struct nl_msg *msg, char **hdr,
1090 char **entry, unsigned int *indent,
1091 enum lnet_nl_key_format fmt)
1093 struct nlattr *list = NULL;
1097 list = nla_nest_start(msg, LN_SCALAR_ATTR_LIST);
1099 yaml_emitter_set_writer_error(out->emitter,
1100 "Emmitter netlink list creation failed");
1102 goto nla_put_failure;
1105 if (fmt & LNKF_FLOW) {
1108 tmp = strchr(*hdr, '{');
1110 tmp = strchr(*hdr, '[');
1112 yaml_emitter_set_writer_error(out->emitter,
1113 "Emmitter flow format invalid");
1115 goto nla_put_failure;
1120 tmp = strchr(*hdr, '}');
1122 tmp = strchr(*hdr, ']');
1124 yaml_emitter_set_writer_error(out->emitter,
1125 "Emmitter flow format invalid");
1127 goto nla_put_failure;
1132 while ((line = strsep(hdr, ",")) != NULL) {
1133 if (isspace(line[0]))
1135 rc = yaml_fill_scalar_data(msg, fmt, line);
1137 goto nla_put_failure;
1139 nla_nest_end(msg, list);
1143 rc = yaml_fill_scalar_data(msg, fmt, *hdr + *indent);
1145 goto nla_put_failure;
1147 line = strsep(entry, "\n");
1149 if (!line || !strlen(line) || strcmp(line, "...") == 0)
1152 fmt = yaml_format_type(out->emitter, line, indent, fmt);
1153 if (fmt == LNKF_END)
1156 if (fmt & ~LNKF_MAPPING) { /* Filter out mappings */
1157 rc = yaml_create_nested_list(out, msg, &line, entry,
1160 goto nla_put_failure;
1162 goto have_next_line;
1164 rc = yaml_fill_scalar_data(msg, fmt, line + *indent);
1166 goto nla_put_failure;
1168 } while (strcmp(line, ""));
1170 nla_nest_end(msg, list);
1171 /* strsep in the above loop moves entry to a value pass the end of the
1172 * nested list. So to avoid losing this value we replace hdr with line
1179 /* YAML allows ' and " in its documents but those characters really
1180 * confuse libc string handling. The workaround is to replace
1181 * ' and " with another reserved character for YAML '%' which is
1182 * for tags which shouldn't matter if we send in a Netlink packet.
1183 * The kernel side will need to handle % in a special way.
1185 static void yaml_quotation_handling(char *buf)
1187 char *tmp = buf, *line;
1189 line = strstr(tmp, "! \'");
1193 while ((line = strchr(tmp, '\"')) != NULL) {
1195 tmp = strchr(line, '\"');
1199 while ((line = strchr(tmp, '\'')) != NULL) {
1201 tmp = strchr(line, '\'');
1206 /* libyaml takes the YAML documents and places the data into an
1207 * internal buffer to the library. We take each line and turn it
1208 * into a Netlink message using the same format as the key table.
1209 * The reason for this approach is that we can do filters at the
1210 * key level or the key + value level.
1212 static int yaml_netlink_write_handler(void *data, unsigned char *buffer,
1215 struct yaml_netlink_output *out = data;
1216 char *buf = strndup((char *)buffer, size);
1217 char *entry = buf, *tmp = buf, *line;
1218 enum lnet_nl_key_format fmt = 0;
1219 struct nl_msg *msg = NULL;
1220 unsigned int indent = 0;
1221 bool nogroups = true;
1224 yaml_quotation_handling(entry);
1226 while (entry && strcmp(line = strsep(&entry, "\n"), "")) {
1228 if (strcmp(line, "---") == 0 || strcmp(line, "...") == 0)
1231 /* In theory we could have a sequence of groups but a bug in
1232 * libyaml prevents this from happing
1234 if (line[0] != ' ' && line[0] != '-') {
1235 tmp = strchr(line, ':');
1240 rc = lustre_netlink_add_group(out->nl, out->family,
1243 yaml_emitter_set_writer_error(out->emitter,
1244 "Netlink group does not exist");
1245 goto nla_put_failure;
1249 /* Handle case first line contains more than a
1253 if (strchr(line, '{') || strchr(line, '['))
1260 msg = nlmsg_alloc();
1262 out->emitter->error = YAML_MEMORY_ERROR;
1263 goto nla_put_failure;
1266 usr_hdr = genlmsg_put(msg, out->pid,
1269 out->flags, out->cmd,
1272 out->emitter->error = YAML_MEMORY_ERROR;
1274 goto nla_put_failure;
1278 fmt = yaml_format_type(out->emitter, line, &indent,
1280 if (fmt & ~LNKF_MAPPING) {
1281 rc = yaml_create_nested_list(out, msg, &line,
1285 yaml_emitter_set_writer_error(out->emitter,
1288 goto nla_put_failure;
1290 /* yaml_created_nested_list set line to the next
1291 * entry. We can just add it to the msg directly.
1294 goto already_have_line;
1296 rc = yaml_fill_scalar_data(msg, fmt,
1299 yaml_emitter_set_writer_error(out->emitter,
1302 goto nla_put_failure;
1308 /* Don't success if no valid groups found */
1310 yaml_emitter_set_writer_error(out->emitter,
1311 "Emitter contains no valid Netlink groups");
1312 goto nla_put_failure;
1316 rc = nl_send_auto(out->nl, msg);
1319 rc = genl_send_simple(out->nl, out->family_id, out->cmd,
1320 out->version, out->flags);
1323 yaml_emitter_set_writer_error(out->emitter,
1327 return out->emitter->error == YAML_NO_ERROR ? 1 : 0;
1330 /* This is the libnl callback for when an error has happened
1331 * kernel side. An error message is sent back to the user.
1333 static int yaml_netlink_write_error(struct sockaddr_nl *who,
1334 struct nlmsgerr *errmsg, void *arg)
1336 struct yaml_netlink_output *data = arg;
1337 struct nlmsghdr *nlh = &errmsg->msg;
1339 if ((nlh->nlmsg_type == NLMSG_ERROR ||
1340 nlh->nlmsg_flags & NLM_F_ACK_TLVS) && errmsg->error) {
1341 const char *errstr = nl_geterror(nl_syserr2nlerr(errmsg->error));
1343 #ifdef HAVE_USRSPC_NLMSGERR
1344 /* Newer kernels support NLM_F_ACK_TLVS in nlmsg_flags
1345 * which gives greater detail why we failed.
1347 if (nlh->nlmsg_flags & NLM_F_ACK_TLVS &&
1348 !(nlh->nlmsg_flags & NLM_F_CAPPED)) {
1349 struct nlattr *head = ((void *)&errmsg->msg);
1350 struct nlattr *tb[NLMSGERR_ATTR_MAX + 1];
1352 if (nla_parse(tb, NLMSGERR_ATTR_MAX + 1, head,
1353 nlmsg_attrlen(nlh, 0), NULL) == 0) {
1354 if (tb[NLMSGERR_ATTR_MSG])
1355 errstr = nla_strdup(tb[NLMSGERR_ATTR_MSG]);
1358 #endif /* HAVE_USRSPC_NLMSGERR */
1359 yaml_emitter_set_writer_error(data->emitter, errstr);
1364 /* This function is used by external utilities to use Netlink with
1365 * libyaml so we can turn YAML documentations into Netlink message
1366 * to send. This behavior mirrors yaml_emitter_set_output_file()
1367 * which is used to write out a YAML document to a file.
1370 yaml_emitter_set_output_netlink(yaml_emitter_t *sender, struct nl_sock *nl,
1371 char *family, int version, int cmd, int flags)
1373 struct yaml_netlink_output *out;
1376 out = calloc(1, sizeof(*out));
1378 sender->error = YAML_MEMORY_ERROR;
1383 out->family_id = genl_ctrl_resolve(nl, family);
1384 if (out->family_id < 0) {
1385 yaml_emitter_set_writer_error(sender,
1386 "failed to resolve Netlink family id");
1391 rc = nl_socket_modify_err_cb(nl, NL_CB_CUSTOM,
1392 yaml_netlink_write_error, out);
1394 yaml_emitter_set_writer_error(sender,
1395 "failed to register error handling");
1400 rc = nl_socket_enable_broadcast_error(nl);
1402 yaml_emitter_set_writer_error(sender,
1403 "failed to enable broadcast errors");
1408 rc = nl_socket_set_ext_ack(nl, true);
1410 yaml_emitter_set_writer_error(sender,
1411 "failed to enable ext ack");
1416 out->emitter = sender;
1418 out->family = family;
1419 out->version = version;
1422 out->pid = nl_socket_get_local_port(nl);
1423 yaml_emitter_set_output(sender, yaml_netlink_write_handler, out);
1427 /* Error handling helpers */
1428 void yaml_emitter_log_error(yaml_emitter_t *emitter, FILE *log)
1430 /* YAML_WRITER_ERROR means no Netlink support so use old API */
1431 switch (emitter->error) {
1432 case YAML_MEMORY_ERROR:
1433 fprintf(log, "Memory error: Not enough memory for emitting\n");
1435 case YAML_WRITER_ERROR:
1436 fprintf(log, "Writer error: %s\n", emitter->problem);
1438 case YAML_EMITTER_ERROR:
1439 fprintf(log, "Emitter error: %s\n", emitter->problem);
1445 void yaml_parser_log_error(yaml_parser_t *parser, FILE *log, const char *errmsg)
1449 switch (parser->error) {
1450 case YAML_MEMORY_ERROR:
1451 fprintf(log, "Memory error: Not enough memory for parser\n");
1454 case YAML_SCANNER_ERROR:
1455 case YAML_PARSER_ERROR:
1456 if (parser->context) {
1458 "%s error: %s at line %d, column %d\n%s at line %d, column %d\n",
1459 parser->error == YAML_SCANNER_ERROR ? "Scanner" : "Parser",
1461 (int)parser->context_mark.line + 1,
1462 (int)parser->context_mark.column + 1,
1464 (int)parser->problem_mark.line + 1,
1465 (int)parser->problem_mark.column + 1);
1467 fprintf(log, "%s error: %s at line %d, column %d\n",
1468 parser->error == YAML_SCANNER_ERROR ? "Scanner" : "Parser",
1470 (int)parser->problem_mark.line + 1,
1471 (int)parser->problem_mark.column + 1);
1475 case YAML_READER_ERROR:
1476 extra = yaml_parser_get_reader_error(parser);
1478 extra = parser->problem;
1480 if (parser->problem_value != -1) {
1481 fprintf(log, "Reader error: '%s':#%X at %ld'\n",
1482 extra, parser->problem_value,
1483 (long)parser->problem_offset);
1485 fprintf(log, "Reader error: '%s' at %ld\n",
1486 extra, (long)parser->problem_offset);