forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
195 lines
4.9 KiB
195 lines
4.9 KiB
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) |
|
|
|
/* |
|
* NETLINK Netlink attributes |
|
* |
|
* Copyright (c) 2003-2013 Thomas Graf <[email protected]> |
|
*/ |
|
|
|
#include <errno.h> |
|
#include <string.h> |
|
#include <stdio.h> |
|
#include <linux/rtnetlink.h> |
|
#include "nlattr.h" |
|
#include "libbpf_internal.h" |
|
|
|
static uint16_t nla_attr_minlen[LIBBPF_NLA_TYPE_MAX+1] = { |
|
[LIBBPF_NLA_U8] = sizeof(uint8_t), |
|
[LIBBPF_NLA_U16] = sizeof(uint16_t), |
|
[LIBBPF_NLA_U32] = sizeof(uint32_t), |
|
[LIBBPF_NLA_U64] = sizeof(uint64_t), |
|
[LIBBPF_NLA_STRING] = 1, |
|
[LIBBPF_NLA_FLAG] = 0, |
|
}; |
|
|
|
static struct nlattr *nla_next(const struct nlattr *nla, int *remaining) |
|
{ |
|
int totlen = NLA_ALIGN(nla->nla_len); |
|
|
|
*remaining -= totlen; |
|
return (struct nlattr *)((void *)nla + totlen); |
|
} |
|
|
|
static int nla_ok(const struct nlattr *nla, int remaining) |
|
{ |
|
return remaining >= sizeof(*nla) && |
|
nla->nla_len >= sizeof(*nla) && |
|
nla->nla_len <= remaining; |
|
} |
|
|
|
static int nla_type(const struct nlattr *nla) |
|
{ |
|
return nla->nla_type & NLA_TYPE_MASK; |
|
} |
|
|
|
static int validate_nla(struct nlattr *nla, int maxtype, |
|
struct libbpf_nla_policy *policy) |
|
{ |
|
struct libbpf_nla_policy *pt; |
|
unsigned int minlen = 0; |
|
int type = nla_type(nla); |
|
|
|
if (type < 0 || type > maxtype) |
|
return 0; |
|
|
|
pt = &policy[type]; |
|
|
|
if (pt->type > LIBBPF_NLA_TYPE_MAX) |
|
return 0; |
|
|
|
if (pt->minlen) |
|
minlen = pt->minlen; |
|
else if (pt->type != LIBBPF_NLA_UNSPEC) |
|
minlen = nla_attr_minlen[pt->type]; |
|
|
|
if (libbpf_nla_len(nla) < minlen) |
|
return -1; |
|
|
|
if (pt->maxlen && libbpf_nla_len(nla) > pt->maxlen) |
|
return -1; |
|
|
|
if (pt->type == LIBBPF_NLA_STRING) { |
|
char *data = libbpf_nla_data(nla); |
|
|
|
if (data[libbpf_nla_len(nla) - 1] != '\0') |
|
return -1; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static inline int nlmsg_len(const struct nlmsghdr *nlh) |
|
{ |
|
return nlh->nlmsg_len - NLMSG_HDRLEN; |
|
} |
|
|
|
/** |
|
* Create attribute index based on a stream of attributes. |
|
* @arg tb Index array to be filled (maxtype+1 elements). |
|
* @arg maxtype Maximum attribute type expected and accepted. |
|
* @arg head Head of attribute stream. |
|
* @arg len Length of attribute stream. |
|
* @arg policy Attribute validation policy. |
|
* |
|
* Iterates over the stream of attributes and stores a pointer to each |
|
* attribute in the index array using the attribute type as index to |
|
* the array. Attribute with a type greater than the maximum type |
|
* specified will be silently ignored in order to maintain backwards |
|
* compatibility. If \a policy is not NULL, the attribute will be |
|
* validated using the specified policy. |
|
* |
|
* @see nla_validate |
|
* @return 0 on success or a negative error code. |
|
*/ |
|
int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, |
|
int len, struct libbpf_nla_policy *policy) |
|
{ |
|
struct nlattr *nla; |
|
int rem, err; |
|
|
|
memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); |
|
|
|
libbpf_nla_for_each_attr(nla, head, len, rem) { |
|
int type = nla_type(nla); |
|
|
|
if (type > maxtype) |
|
continue; |
|
|
|
if (policy) { |
|
err = validate_nla(nla, maxtype, policy); |
|
if (err < 0) |
|
goto errout; |
|
} |
|
|
|
if (tb[type]) |
|
pr_warn("Attribute of type %#x found multiple times in message, " |
|
"previous attribute is being ignored.\n", type); |
|
|
|
tb[type] = nla; |
|
} |
|
|
|
err = 0; |
|
errout: |
|
return err; |
|
} |
|
|
|
/** |
|
* Create attribute index based on nested attribute |
|
* @arg tb Index array to be filled (maxtype+1 elements). |
|
* @arg maxtype Maximum attribute type expected and accepted. |
|
* @arg nla Nested Attribute. |
|
* @arg policy Attribute validation policy. |
|
* |
|
* Feeds the stream of attributes nested into the specified attribute |
|
* to libbpf_nla_parse(). |
|
* |
|
* @see libbpf_nla_parse |
|
* @return 0 on success or a negative error code. |
|
*/ |
|
int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype, |
|
struct nlattr *nla, |
|
struct libbpf_nla_policy *policy) |
|
{ |
|
return libbpf_nla_parse(tb, maxtype, libbpf_nla_data(nla), |
|
libbpf_nla_len(nla), policy); |
|
} |
|
|
|
/* dump netlink extended ack error message */ |
|
int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh) |
|
{ |
|
struct libbpf_nla_policy extack_policy[NLMSGERR_ATTR_MAX + 1] = { |
|
[NLMSGERR_ATTR_MSG] = { .type = LIBBPF_NLA_STRING }, |
|
[NLMSGERR_ATTR_OFFS] = { .type = LIBBPF_NLA_U32 }, |
|
}; |
|
struct nlattr *tb[NLMSGERR_ATTR_MAX + 1], *attr; |
|
struct nlmsgerr *err; |
|
char *errmsg = NULL; |
|
int hlen, alen; |
|
|
|
/* no TLVs, nothing to do here */ |
|
if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS)) |
|
return 0; |
|
|
|
err = (struct nlmsgerr *)NLMSG_DATA(nlh); |
|
hlen = sizeof(*err); |
|
|
|
/* if NLM_F_CAPPED is set then the inner err msg was capped */ |
|
if (!(nlh->nlmsg_flags & NLM_F_CAPPED)) |
|
hlen += nlmsg_len(&err->msg); |
|
|
|
attr = (struct nlattr *) ((void *) err + hlen); |
|
alen = nlh->nlmsg_len - hlen; |
|
|
|
if (libbpf_nla_parse(tb, NLMSGERR_ATTR_MAX, attr, alen, |
|
extack_policy) != 0) { |
|
pr_warn("Failed to parse extended error attributes\n"); |
|
return 0; |
|
} |
|
|
|
if (tb[NLMSGERR_ATTR_MSG]) |
|
errmsg = (char *) libbpf_nla_data(tb[NLMSGERR_ATTR_MSG]); |
|
|
|
pr_warn("Kernel error message: %s\n", errmsg); |
|
|
|
return 0; |
|
}
|
|
|