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NetworkManager/shared/nm-platform/nm-netlink.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2018 Red Hat, Inc.
*/
#include "nm-glib-aux/nm-default-glib-i18n-lib.h"
#include "nm-netlink.h"
#include <unistd.h>
#include <fcntl.h>
/*****************************************************************************/
#ifndef SOL_NETLINK
#define SOL_NETLINK 270
#endif
/*****************************************************************************/
#define NL_SOCK_PASSCRED (1 << 1)
#define NL_MSG_PEEK (1 << 3)
#define NL_MSG_PEEK_EXPLICIT (1 << 4)
#define NL_NO_AUTO_ACK (1 << 5)
#ifndef NETLINK_EXT_ACK
#define NETLINK_EXT_ACK 11
#endif
struct nl_msg {
int nm_protocol;
struct sockaddr_nl nm_src;
struct sockaddr_nl nm_dst;
struct ucred nm_creds;
struct nlmsghdr * nm_nlh;
size_t nm_size;
bool nm_creds_has : 1;
};
struct nl_sock {
struct sockaddr_nl s_local;
struct sockaddr_nl s_peer;
int s_fd;
int s_proto;
unsigned int s_seq_next;
unsigned int s_seq_expect;
int s_flags;
size_t s_bufsize;
};
/*****************************************************************************/
NM_UTILS_ENUM2STR_DEFINE(nl_nlmsgtype2str,
int,
NM_UTILS_ENUM2STR(NLMSG_NOOP, "NOOP"),
NM_UTILS_ENUM2STR(NLMSG_ERROR, "ERROR"),
NM_UTILS_ENUM2STR(NLMSG_DONE, "DONE"),
NM_UTILS_ENUM2STR(NLMSG_OVERRUN, "OVERRUN"), );
NM_UTILS_FLAGS2STR_DEFINE(nl_nlmsg_flags2str,
int,
NM_UTILS_FLAGS2STR(NLM_F_REQUEST, "REQUEST"),
NM_UTILS_FLAGS2STR(NLM_F_MULTI, "MULTI"),
NM_UTILS_FLAGS2STR(NLM_F_ACK, "ACK"),
NM_UTILS_FLAGS2STR(NLM_F_ECHO, "ECHO"),
NM_UTILS_FLAGS2STR(NLM_F_ROOT, "ROOT"),
NM_UTILS_FLAGS2STR(NLM_F_MATCH, "MATCH"),
NM_UTILS_FLAGS2STR(NLM_F_ATOMIC, "ATOMIC"),
NM_UTILS_FLAGS2STR(NLM_F_REPLACE, "REPLACE"),
NM_UTILS_FLAGS2STR(NLM_F_EXCL, "EXCL"),
NM_UTILS_FLAGS2STR(NLM_F_CREATE, "CREATE"),
NM_UTILS_FLAGS2STR(NLM_F_APPEND, "APPEND"), );
/*****************************************************************************/
const char *
nl_nlmsghdr_to_str(const struct nlmsghdr *hdr, char *buf, gsize len)
{
const char *b;
const char *s;
guint flags, flags_before;
const char *prefix;
if (!nm_utils_to_string_buffer_init_null(hdr, &buf, &len))
return buf;
b = buf;
switch (hdr->nlmsg_type) {
case RTM_GETLINK:
s = "RTM_GETLINK";
break;
case RTM_NEWLINK:
s = "RTM_NEWLINK";
break;
case RTM_DELLINK:
s = "RTM_DELLINK";
break;
case RTM_SETLINK:
s = "RTM_SETLINK";
break;
case RTM_GETADDR:
s = "RTM_GETADDR";
break;
case RTM_NEWADDR:
s = "RTM_NEWADDR";
break;
case RTM_DELADDR:
s = "RTM_DELADDR";
break;
case RTM_GETROUTE:
s = "RTM_GETROUTE";
break;
case RTM_NEWROUTE:
s = "RTM_NEWROUTE";
break;
case RTM_DELROUTE:
s = "RTM_DELROUTE";
break;
case RTM_GETRULE:
s = "RTM_GETRULE";
break;
case RTM_NEWRULE:
s = "RTM_NEWRULE";
break;
case RTM_DELRULE:
s = "RTM_DELRULE";
break;
case RTM_GETQDISC:
s = "RTM_GETQDISC";
break;
case RTM_NEWQDISC:
s = "RTM_NEWQDISC";
break;
case RTM_DELQDISC:
s = "RTM_DELQDISC";
break;
case RTM_GETTFILTER:
s = "RTM_GETTFILTER";
break;
case RTM_NEWTFILTER:
s = "RTM_NEWTFILTER";
break;
case RTM_DELTFILTER:
s = "RTM_DELTFILTER";
break;
case NLMSG_NOOP:
s = "NLMSG_NOOP";
break;
case NLMSG_ERROR:
s = "NLMSG_ERROR";
break;
case NLMSG_DONE:
s = "NLMSG_DONE";
break;
case NLMSG_OVERRUN:
s = "NLMSG_OVERRUN";
break;
default:
s = NULL;
break;
}
if (s)
nm_utils_strbuf_append_str(&buf, &len, s);
else
nm_utils_strbuf_append(&buf, &len, "(%u)", (unsigned) hdr->nlmsg_type);
flags = hdr->nlmsg_flags;
if (!flags) {
nm_utils_strbuf_append_str(&buf, &len, ", flags 0");
goto flags_done;
}
#define _F(f, n) \
G_STMT_START \
{ \
if (NM_FLAGS_ALL(flags, f)) { \
flags &= ~(f); \
nm_utils_strbuf_append(&buf, &len, "%s%s", prefix, n); \
if (!flags) \
goto flags_done; \
prefix = ","; \
} \
} \
G_STMT_END
prefix = ", flags ";
flags_before = flags;
_F(NLM_F_REQUEST, "request");
_F(NLM_F_MULTI, "multi");
_F(NLM_F_ACK, "ack");
_F(NLM_F_ECHO, "echo");
_F(NLM_F_DUMP_INTR, "dump_intr");
_F(0x20 /*NLM_F_DUMP_FILTERED*/, "dump_filtered");
if (flags_before != flags)
prefix = ";";
switch (hdr->nlmsg_type) {
case RTM_NEWLINK:
case RTM_NEWADDR:
case RTM_NEWROUTE:
case RTM_NEWQDISC:
case RTM_NEWTFILTER:
_F(NLM_F_REPLACE, "replace");
_F(NLM_F_EXCL, "excl");
_F(NLM_F_CREATE, "create");
_F(NLM_F_APPEND, "append");
break;
case RTM_GETLINK:
case RTM_GETADDR:
case RTM_GETROUTE:
case RTM_DELQDISC:
case RTM_DELTFILTER:
_F(NLM_F_DUMP, "dump");
_F(NLM_F_ROOT, "root");
_F(NLM_F_MATCH, "match");
_F(NLM_F_ATOMIC, "atomic");
break;
}
#undef _F
if (flags_before != flags)
prefix = ";";
nm_utils_strbuf_append(&buf, &len, "%s0x%04x", prefix, flags);
flags_done:
nm_utils_strbuf_append(&buf, &len, ", seq %u", (unsigned) hdr->nlmsg_seq);
return b;
}
/*****************************************************************************/
struct nlmsghdr *
nlmsg_hdr(struct nl_msg *n)
{
return n->nm_nlh;
}
void *
nlmsg_reserve(struct nl_msg *n, size_t len, int pad)
{
char * buf = (char *) n->nm_nlh;
size_t nlmsg_len = n->nm_nlh->nlmsg_len;
size_t tlen;
nm_assert(pad >= 0);
if (len > n->nm_size)
return NULL;
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);
return buf;
}
/*****************************************************************************/
struct nlattr *
nla_reserve(struct nl_msg *msg, int attrtype, int attrlen)
{
struct nlattr *nla;
int tlen;
if (attrlen < 0)
return NULL;
tlen = NLMSG_ALIGN(msg->nm_nlh->nlmsg_len) + nla_total_size(attrlen);
if (tlen > msg->nm_size)
return NULL;
nla = (struct nlattr *) nlmsg_tail(msg->nm_nlh);
nla->nla_type = attrtype;
nla->nla_len = nla_attr_size(attrlen);
if (attrlen)
memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
msg->nm_nlh->nlmsg_len = tlen;
return nla;
}
/*****************************************************************************/
struct nl_msg *
nlmsg_alloc_size(size_t len)
{
struct nl_msg *nm;
if (len < sizeof(struct nlmsghdr))
len = sizeof(struct nlmsghdr);
nm = g_slice_new(struct nl_msg);
*nm = (struct nl_msg){
.nm_protocol = -1,
.nm_size = len,
.nm_nlh = g_malloc0(len),
};
nm->nm_nlh->nlmsg_len = nlmsg_total_size(0);
return nm;
}
/**
* 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_size(nm_utils_getpagesize());
}
struct nl_msg *
nlmsg_alloc_convert(struct nlmsghdr *hdr)
{
struct nl_msg *nm;
nm = nlmsg_alloc_size(NLMSG_ALIGN(hdr->nlmsg_len));
memcpy(nm->nm_nlh, hdr, hdr->nlmsg_len);
return nm;
}
struct nl_msg *
nlmsg_alloc_simple(int nlmsgtype, int flags)
{
struct nl_msg *nm;
struct nlmsghdr *new;
nm = nlmsg_alloc();
new = nm->nm_nlh;
new->nlmsg_type = nlmsgtype;
new->nlmsg_flags = flags;
return nm;
}
void
nlmsg_free(struct nl_msg *msg)
{
if (!msg)
return;
g_free(msg->nm_nlh);
g_slice_free(struct nl_msg, msg);
}
/*****************************************************************************/
int
nlmsg_append(struct nl_msg *n, const void *data, size_t len, int pad)
{
void *tmp;
nm_assert(n);
nm_assert(data);
nm_assert(len > 0);
nm_assert(pad >= 0);
tmp = nlmsg_reserve(n, len, pad);
if (tmp == NULL)
return -ENOMEM;
memcpy(tmp, data, len);
return 0;
}
/*****************************************************************************/
int
nlmsg_parse(struct nlmsghdr * nlh,
int hdrlen,
struct nlattr * tb[],
int maxtype,
const struct nla_policy *policy)
{
if (!nlmsg_valid_hdr(nlh, hdrlen))
return -NME_NL_MSG_TOOSHORT;
return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen), nlmsg_attrlen(nlh, hdrlen), policy);
}
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)
g_return_val_if_reached(NULL);
nlh = (struct nlmsghdr *) n->nm_nlh;
nlh->nlmsg_type = type;
nlh->nlmsg_flags = flags;
nlh->nlmsg_pid = pid;
nlh->nlmsg_seq = seq;
if (payload > 0 && nlmsg_reserve(n, payload, NLMSG_ALIGNTO) == NULL)
return NULL;
return nlh;
}
size_t
nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
{
const char *src;
size_t srclen;
size_t len;
/* - Always writes @dstsize bytes to @dst
* - Copies the first non-NUL characters to @dst.
* Any characters after the first NUL bytes in @nla are ignored.
* - If the string @nla is longer than @dstsize, the string
* gets truncated. @dst will always be NUL terminated. */
if (G_UNLIKELY(dstsize <= 1)) {
if (dstsize == 1)
dst[0] = '\0';
if (nla && (srclen = nla_len(nla)) > 0)
return strnlen(nla_data(nla), srclen);
return 0;
}
nm_assert(dst);
if (nla) {
srclen = nla_len(nla);
if (srclen > 0) {
src = nla_data(nla);
srclen = strnlen(src, srclen);
if (srclen > 0) {
len = NM_MIN(dstsize - 1, srclen);
memcpy(dst, src, len);
memset(&dst[len], 0, dstsize - len);
return srclen;
}
}
}
memset(dst, 0, dstsize);
return 0;
}
size_t
nla_memcpy(void *dst, const struct nlattr *nla, size_t dstsize)
{
size_t len;
int srclen;
if (!nla)
return 0;
srclen = nla_len(nla);
if (srclen <= 0) {
nm_assert(srclen == 0);
return 0;
}
len = NM_MIN((size_t) srclen, dstsize);
if (len > 0) {
/* there is a crucial difference between nla_strlcpy() and nla_memcpy().
* The former always write @dstsize bytes (akin to strncpy()), here, we only
* write the bytes that we actually have (leaving the remainder undefined). */
memcpy(dst, nla_data(nla), len);
}
return srclen;
}
int
nla_put(struct nl_msg *msg, int attrtype, int datalen, const void *data)
{
struct nlattr *nla;
nla = nla_reserve(msg, attrtype, datalen);
if (!nla) {
if (datalen < 0)
g_return_val_if_reached(-NME_BUG);
return -ENOMEM;
}
if (datalen > 0)
memcpy(nla_data(nla), data, datalen);
return 0;
}
struct nlattr *
nla_find(const struct nlattr *head, int len, int attrtype)
{
const struct nlattr *nla;
int rem;
nla_for_each_attr (nla, head, len, rem) {
if (nla_type(nla) == attrtype)
return (struct nlattr *) nla;
}
return NULL;
}
void
nla_nest_cancel(struct nl_msg *msg, const struct nlattr *attr)
{
ssize_t len;
len = (char *) nlmsg_tail(msg->nm_nlh) - (char *) attr;
if (len < 0)
g_return_if_reached();
else if (len > 0) {
msg->nm_nlh->nlmsg_len -= len;
memset(nlmsg_tail(msg->nm_nlh), 0, len);
}
}
struct nlattr *
nla_nest_start(struct nl_msg *msg, int attrtype)
{
struct nlattr *start = (struct nlattr *) nlmsg_tail(msg->nm_nlh);
if (nla_put(msg, NLA_F_NESTED | attrtype, 0, NULL) < 0)
return NULL;
return start;
}
static int
_nest_end(struct nl_msg *msg, struct nlattr *start, int keep_empty)
{
size_t pad, len;
len = (char *) nlmsg_tail(msg->nm_nlh) - (char *) start;
if (len > USHRT_MAX || (!keep_empty && len == NLA_HDRLEN)) {
/*
* Max nlattr size exceeded or empty nested attribute, trim the
* attribute header again
*/
nla_nest_cancel(msg, start);
/* Return error only if nlattr size was exceeded */
return (len == NLA_HDRLEN) ? 0 : -NME_NL_ATTRSIZE;
}
start->nla_len = len;
pad = NLMSG_ALIGN(msg->nm_nlh->nlmsg_len) - msg->nm_nlh->nlmsg_len;
if (pad > 0) {
/*
* Data inside attribute does not end at a alignment boundary.
* Pad accordingly and account for the additional space in
* the message. nlmsg_reserve() may never fail in this situation,
* the allocate message buffer must be a multiple of NLMSG_ALIGNTO.
*/
if (!nlmsg_reserve(msg, pad, 0))
g_return_val_if_reached(-NME_BUG);
}
return 0;
}
int
nla_nest_end(struct nl_msg *msg, struct nlattr *start)
{
return _nest_end(msg, start, 0);
}
static const uint16_t nla_attr_minlen[NLA_TYPE_MAX + 1] = {
[NLA_U8] = sizeof(uint8_t),
[NLA_U16] = sizeof(uint16_t),
[NLA_U32] = sizeof(uint32_t),
[NLA_U64] = sizeof(uint64_t),
[NLA_STRING] = 1,
[NLA_FLAG] = 0,
};
static int
validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy)
{
const struct 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 > NLA_TYPE_MAX)
g_return_val_if_reached(-NME_BUG);
if (pt->minlen)
minlen = pt->minlen;
else if (pt->type != NLA_UNSPEC)
minlen = nla_attr_minlen[pt->type];
if (nla_len(nla) < minlen)
return -NME_UNSPEC;
if (pt->maxlen && nla_len(nla) > pt->maxlen)
return -NME_UNSPEC;
if (pt->type == NLA_STRING) {
const char *data;
nm_assert(minlen > 0);
data = nla_data(nla);
if (data[nla_len(nla) - 1] != '\0')
return -NME_UNSPEC;
}
return 0;
}
int
nla_parse(struct nlattr * tb[],
int maxtype,
struct nlattr * head,
int len,
const struct nla_policy *policy)
{
struct nlattr *nla;
int rem, nmerr;
memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
nla_for_each_attr (nla, head, len, rem) {
int type = nla_type(nla);
if (type > maxtype)
continue;
if (policy) {
nmerr = validate_nla(nla, maxtype, policy);
if (nmerr < 0)
return nmerr;
}
tb[type] = nla;
}
return 0;
}
/*****************************************************************************/
int
nlmsg_get_proto(struct nl_msg *msg)
{
return msg->nm_protocol;
}
void
nlmsg_set_proto(struct nl_msg *msg, int protocol)
{
msg->nm_protocol = protocol;
}
void
nlmsg_set_src(struct nl_msg *msg, struct sockaddr_nl *addr)
{
memcpy(&msg->nm_src, addr, sizeof(*addr));
}
struct ucred *
nlmsg_get_creds(struct nl_msg *msg)
{
if (msg->nm_creds_has)
return &msg->nm_creds;
return NULL;
}
void
nlmsg_set_creds(struct nl_msg *msg, struct ucred *creds)
{
if (creds) {
memcpy(&msg->nm_creds, creds, sizeof(*creds));
msg->nm_creds_has = TRUE;
} else
msg->nm_creds_has = FALSE;
}
/*****************************************************************************/
void *
genlmsg_put(struct nl_msg *msg,
uint32_t port,
uint32_t seq,
int family,
int hdrlen,
int flags,
uint8_t cmd,
uint8_t version)
{
struct nlmsghdr * nlh;
struct genlmsghdr hdr = {
.cmd = cmd,
.version = version,
};
nlh = nlmsg_put(msg, port, seq, family, GENL_HDRLEN + hdrlen, flags);
if (nlh == NULL)
return NULL;
memcpy(nlmsg_data(nlh), &hdr, sizeof(hdr));
return (char *) nlmsg_data(nlh) + GENL_HDRLEN;
}
void *
genlmsg_data(const struct genlmsghdr *gnlh)
{
return ((unsigned char *) gnlh + GENL_HDRLEN);
}
void *
genlmsg_user_hdr(const struct genlmsghdr *gnlh)
{
return genlmsg_data(gnlh);
}
struct genlmsghdr *
genlmsg_hdr(struct nlmsghdr *nlh)
{
return nlmsg_data(nlh);
}
void *
genlmsg_user_data(const struct genlmsghdr *gnlh, const int hdrlen)
{
return (char *) genlmsg_user_hdr(gnlh) + NLMSG_ALIGN(hdrlen);
}
struct nlattr *
genlmsg_attrdata(const struct genlmsghdr *gnlh, int hdrlen)
{
return genlmsg_user_data(gnlh, hdrlen);
}
int
genlmsg_len(const struct genlmsghdr *gnlh)
{
const struct nlmsghdr *nlh;
nlh = (const struct nlmsghdr *) ((const unsigned char *) gnlh - NLMSG_HDRLEN);
return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
}
int
genlmsg_attrlen(const struct genlmsghdr *gnlh, int hdrlen)
{
return genlmsg_len(gnlh) - NLMSG_ALIGN(hdrlen);
}
int
genlmsg_valid_hdr(struct nlmsghdr *nlh, int hdrlen)
{
struct genlmsghdr *ghdr;
if (!nlmsg_valid_hdr(nlh, GENL_HDRLEN))
return 0;
ghdr = nlmsg_data(nlh);
if (genlmsg_len(ghdr) < NLMSG_ALIGN(hdrlen))
return 0;
return 1;
}
int
genlmsg_parse(struct nlmsghdr * nlh,
int hdrlen,
struct nlattr * tb[],
int maxtype,
const struct nla_policy *policy)
{
struct genlmsghdr *ghdr;
if (!genlmsg_valid_hdr(nlh, hdrlen))
return -NME_NL_MSG_TOOSHORT;
ghdr = nlmsg_data(nlh);
return nla_parse(tb,
maxtype,
genlmsg_attrdata(ghdr, hdrlen),
genlmsg_attrlen(ghdr, hdrlen),
policy);
}
static int
_genl_parse_getfamily(struct nl_msg *msg, void *arg)
{
static const struct nla_policy ctrl_policy[] = {
[CTRL_ATTR_FAMILY_ID] = {.type = NLA_U16},
[CTRL_ATTR_FAMILY_NAME] = {.type = NLA_STRING, .maxlen = GENL_NAMSIZ},
[CTRL_ATTR_VERSION] = {.type = NLA_U32},
[CTRL_ATTR_HDRSIZE] = {.type = NLA_U32},
[CTRL_ATTR_MAXATTR] = {.type = NLA_U32},
[CTRL_ATTR_OPS] = {.type = NLA_NESTED},
[CTRL_ATTR_MCAST_GROUPS] = {.type = NLA_NESTED},
};
struct nlattr * tb[G_N_ELEMENTS(ctrl_policy)];
struct nlmsghdr *nlh = nlmsg_hdr(msg);
gint32 * response_data = arg;
if (genlmsg_parse_arr(nlh, 0, tb, ctrl_policy) < 0)
return NL_SKIP;
if (tb[CTRL_ATTR_FAMILY_ID])
*response_data = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
return NL_STOP;
}
int
genl_ctrl_resolve(struct nl_sock *sk, const char *name)
{
nm_auto_nlmsg struct nl_msg *msg = NULL;
int nmerr;
gint32 response_data = -1;
const struct nl_cb cb = {
.valid_cb = _genl_parse_getfamily,
.valid_arg = &response_data,
};
msg = nlmsg_alloc();
if (!genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, GENL_ID_CTRL, 0, 0, CTRL_CMD_GETFAMILY, 1))
return -ENOMEM;
nmerr = nla_put_string(msg, CTRL_ATTR_FAMILY_NAME, name);
if (nmerr < 0)
return nmerr;
nmerr = nl_send_auto(sk, msg);
if (nmerr < 0)
return nmerr;
nmerr = nl_recvmsgs(sk, &cb);
if (nmerr < 0)
return nmerr;
/* If search was successful, request may be ACKed after data */
nmerr = nl_wait_for_ack(sk, NULL);
if (nmerr < 0)
return nmerr;
if (response_data < 0)
return -NME_UNSPEC;
return response_data;
}
/*****************************************************************************/
struct nl_sock *
nl_socket_alloc(void)
{
struct nl_sock *sk;
sk = g_slice_new0(struct nl_sock);
sk->s_fd = -1;
sk->s_local.nl_family = AF_NETLINK;
sk->s_peer.nl_family = AF_NETLINK;
sk->s_seq_expect = sk->s_seq_next = time(NULL);
return sk;
}
void
nl_socket_free(struct nl_sock *sk)
{
if (!sk)
return;
if (sk->s_fd >= 0)
nm_close(sk->s_fd);
g_slice_free(struct nl_sock, sk);
}
int
nl_socket_get_fd(const struct nl_sock *sk)
{
return sk->s_fd;
}
uint32_t
nl_socket_get_local_port(const struct nl_sock *sk)
{
return sk->s_local.nl_pid;
}
size_t
nl_socket_get_msg_buf_size(struct nl_sock *sk)
{
return sk->s_bufsize;
}
int
nl_socket_set_passcred(struct nl_sock *sk, int state)
{
int err;
if (sk->s_fd == -1)
return -NME_NL_BAD_SOCK;
err = setsockopt(sk->s_fd, SOL_SOCKET, SO_PASSCRED, &state, sizeof(state));
if (err < 0)
return -nm_errno_from_native(errno);
if (state)
sk->s_flags |= NL_SOCK_PASSCRED;
else
sk->s_flags &= ~NL_SOCK_PASSCRED;
return 0;
}
int
nl_socket_set_msg_buf_size(struct nl_sock *sk, size_t bufsize)
{
sk->s_bufsize = bufsize;
return 0;
}
struct sockaddr_nl *
nlmsg_get_dst(struct nl_msg *msg)
{
return &msg->nm_dst;
}
int
nl_socket_set_nonblocking(const struct nl_sock *sk)
{
if (sk->s_fd == -1)
return -NME_NL_BAD_SOCK;
if (fcntl(sk->s_fd, F_SETFL, O_NONBLOCK) < 0)
return -nm_errno_from_native(errno);
return 0;
}
int
nl_socket_set_buffer_size(struct nl_sock *sk, int rxbuf, int txbuf)
{
int err;
if (rxbuf <= 0)
rxbuf = 32768;
if (txbuf <= 0)
txbuf = 32768;
if (sk->s_fd == -1)
return -NME_NL_BAD_SOCK;
err = setsockopt(sk->s_fd, SOL_SOCKET, SO_SNDBUF, &txbuf, sizeof(txbuf));
if (err < 0) {
return -nm_errno_from_native(errno);
}
err = setsockopt(sk->s_fd, SOL_SOCKET, SO_RCVBUF, &rxbuf, sizeof(rxbuf));
if (err < 0) {
return -nm_errno_from_native(errno);
}
return 0;
}
int
nl_socket_add_memberships(struct nl_sock *sk, int group, ...)
{
int err;
va_list ap;
if (sk->s_fd == -1)
return -NME_NL_BAD_SOCK;
va_start(ap, group);
while (group != 0) {
if (group < 0) {
va_end(ap);
g_return_val_if_reached(-NME_BUG);
}
err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
if (err < 0) {
int errsv = errno;
va_end(ap);
return -nm_errno_from_native(errsv);
}
group = va_arg(ap, int);
}
va_end(ap);
return 0;
}
int
nl_socket_set_ext_ack(struct nl_sock *sk, gboolean enable)
{
int err, val;
if (sk->s_fd == -1)
return -NME_NL_BAD_SOCK;
val = !!enable;
err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_EXT_ACK, &val, sizeof(val));
if (err < 0)
return -nm_errno_from_native(errno);
return 0;
}
void
nl_socket_disable_msg_peek(struct nl_sock *sk)
{
sk->s_flags |= NL_MSG_PEEK_EXPLICIT;
sk->s_flags &= ~NL_MSG_PEEK;
}
int
nl_connect(struct nl_sock *sk, int protocol)
{
int err, nmerr;
socklen_t addrlen;
struct sockaddr_nl local = {0};
if (sk->s_fd != -1)
return -NME_NL_BAD_SOCK;
sk->s_fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
if (sk->s_fd < 0) {
nmerr = -nm_errno_from_native(errno);
goto errout;
}
nmerr = nl_socket_set_buffer_size(sk, 0, 0);
if (nmerr < 0)
goto errout;
nm_assert(sk->s_local.nl_pid == 0);
err = bind(sk->s_fd, (struct sockaddr *) &sk->s_local, sizeof(sk->s_local));
if (err != 0) {
nmerr = -nm_errno_from_native(errno);
goto errout;
}
addrlen = sizeof(local);
err = getsockname(sk->s_fd, (struct sockaddr *) &local, &addrlen);
if (err < 0) {
nmerr = -nm_errno_from_native(errno);
goto errout;
}
if (addrlen != sizeof(local)) {
nmerr = -NME_UNSPEC;
goto errout;
}
if (local.nl_family != AF_NETLINK) {
nmerr = -NME_UNSPEC;
goto errout;
}
sk->s_local = local;
sk->s_proto = protocol;
return 0;
errout:
if (sk->s_fd != -1) {
close(sk->s_fd);
sk->s_fd = -1;
}
return nmerr;
}
/*****************************************************************************/
static void
_cb_init(struct nl_cb *dst, const struct nl_cb *src)
{
nm_assert(dst);
if (src)
*dst = *src;
else
memset(dst, 0, sizeof(*dst));
}
static int
ack_wait_handler(struct nl_msg *msg, void *arg)
{
return NL_STOP;
}
int
nl_wait_for_ack(struct nl_sock *sk, const struct nl_cb *cb)
{
struct nl_cb cb2;
_cb_init(&cb2, cb);
cb2.ack_cb = ack_wait_handler;
return nl_recvmsgs(sk, &cb2);
}
#define NL_CB_CALL(cb, type, msg) \
do { \
const struct nl_cb *_cb = (cb); \
\
if (_cb && _cb->type##_cb) { \
/* the returned value here must be either a negative
* netlink error number, or one of NL_SKIP, NL_STOP, NL_OK. */ \
nmerr = _cb->type##_cb((msg), _cb->type##_arg); \
switch (nmerr) { \
case NL_OK: \
nm_assert(nmerr == 0); \
break; \
case NL_SKIP: \
goto skip; \
case NL_STOP: \
goto stop; \
default: \
if (nmerr >= 0) { \
nm_assert_not_reached(); \
nmerr = -NME_BUG; \
} \
goto out; \
} \
} \
} while (0)
int
nl_recvmsgs(struct nl_sock *sk, const struct nl_cb *cb)
{
int n, nmerr = 0, multipart = 0, interrupted = 0, nrecv = 0;
gs_free unsigned char *buf = NULL;
struct nlmsghdr * hdr;
struct sockaddr_nl nla = {0};
struct ucred creds;
gboolean creds_has;
continue_reading:
n = nl_recv(sk, &nla, &buf, &creds, &creds_has);
if (n <= 0)
return n;
hdr = (struct nlmsghdr *) buf;
while (nlmsg_ok(hdr, n)) {
nm_auto_nlmsg struct nl_msg *msg = NULL;
msg = nlmsg_alloc_convert(hdr);
nlmsg_set_proto(msg, sk->s_proto);
nlmsg_set_src(msg, &nla);
nlmsg_set_creds(msg, creds_has ? &creds : NULL);
nrecv++;
/* Only do sequence checking if auto-ack mode is enabled */
if (!(sk->s_flags & NL_NO_AUTO_ACK)) {
if (hdr->nlmsg_seq != sk->s_seq_expect) {
nmerr = -NME_NL_SEQ_MISMATCH;
goto out;
}
}
if (hdr->nlmsg_type == NLMSG_DONE || hdr->nlmsg_type == NLMSG_ERROR
|| hdr->nlmsg_type == NLMSG_NOOP || hdr->nlmsg_type == NLMSG_OVERRUN) {
/* We can't check for !NLM_F_MULTI since some netlink
* users in the kernel are broken. */
sk->s_seq_expect++;
}
if (hdr->nlmsg_flags & NLM_F_MULTI)
multipart = 1;
if (hdr->nlmsg_flags & NLM_F_DUMP_INTR) {
/*
* We have to continue reading to clear
* all messages until a NLMSG_DONE is
* received and report the inconsistency.
*/
interrupted = 1;
}
/* messages terminates a multipart message, this is
* usually the end of a message and therefore we slip
* out of the loop by default. the user may overrule
* this action by skipping this packet. */
if (hdr->nlmsg_type == NLMSG_DONE) {
multipart = 0;
NL_CB_CALL(cb, finish, msg);
}
/* Message to be ignored, the default action is to
* skip this message if no callback is specified. The
* user may overrule this action by returning
* NL_PROCEED. */
else if (hdr->nlmsg_type == NLMSG_NOOP)
goto skip;
/* Data got lost, report back to user. The default action is to
* quit parsing. The user may overrule this action by returning
* NL_SKIP or NL_PROCEED (dangerous) */
else if (hdr->nlmsg_type == NLMSG_OVERRUN) {
nmerr = -NME_NL_MSG_OVERFLOW;
goto out;
}
/* Message carries a nlmsgerr */
else if (hdr->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *e = nlmsg_data(hdr);
if (hdr->nlmsg_len < nlmsg_size(sizeof(*e))) {
/* Truncated error message, the default action
* is to stop parsing. The user may overrule
* this action by returning NL_SKIP or
* NL_PROCEED (dangerous) */
nmerr = -NME_NL_MSG_TRUNC;
goto out;
}
if (e->error) {
/* Error message reported back from kernel. */
if (cb && cb->err_cb) {
/* the returned value here must be either a negative
* netlink error number, or one of NL_SKIP, NL_STOP, NL_OK. */
nmerr = cb->err_cb(&nla, e, cb->err_arg);
if (nmerr < 0)
goto out;
else if (nmerr == NL_SKIP)
goto skip;
else if (nmerr == NL_STOP) {
nmerr = -nm_errno_from_native(e->error);
goto out;
}
nm_assert(nmerr == NL_OK);
} else {
nmerr = -nm_errno_from_native(e->error);
goto out;
}
} else
NL_CB_CALL(cb, ack, msg);
} else {
/* Valid message (not checking for MULTIPART bit to
* get along with broken kernels. NL_SKIP has no
* effect on this. */
NL_CB_CALL(cb, valid, msg);
}
skip:
nmerr = 0;
hdr = nlmsg_next(hdr, &n);
}
if (multipart) {
/* Multipart message not yet complete, continue reading */
nm_clear_g_free(&buf);
nmerr = 0;
goto continue_reading;
}
stop:
nmerr = 0;
out:
if (interrupted)
nmerr = -NME_NL_DUMP_INTR;
nm_assert(nmerr <= 0);
return nmerr ?: nrecv;
}
int
nl_sendmsg(struct nl_sock *sk, struct nl_msg *msg, struct msghdr *hdr)
{
int ret;
if (sk->s_fd < 0)
return -NME_NL_BAD_SOCK;
nlmsg_set_src(msg, &sk->s_local);
ret = sendmsg(sk->s_fd, hdr, 0);
if (ret < 0)
return -nm_errno_from_native(errno);
return ret;
}
int
nl_send_iovec(struct nl_sock *sk, struct nl_msg *msg, struct iovec *iov, unsigned iovlen)
{
struct sockaddr_nl *dst;
struct ucred * creds;
struct msghdr hdr = {
.msg_name = (void *) &sk->s_peer,
.msg_namelen = sizeof(struct sockaddr_nl),
.msg_iov = iov,
.msg_iovlen = iovlen,
};
char buf[CMSG_SPACE(sizeof(struct ucred))];
/* Overwrite destination if specified in the message itself, defaults
* to the peer address of the socket.
*/
dst = nlmsg_get_dst(msg);
if (dst->nl_family == AF_NETLINK)
hdr.msg_name = dst;
/* Add credentials if present. */
creds = nlmsg_get_creds(msg);
if (creds != NULL) {
struct cmsghdr *cmsg;
hdr.msg_control = buf;
hdr.msg_controllen = sizeof(buf);
cmsg = CMSG_FIRSTHDR(&hdr);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_CREDENTIALS;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
memcpy(CMSG_DATA(cmsg), creds, sizeof(struct ucred));
}
return nl_sendmsg(sk, msg, &hdr);
}
void
nl_complete_msg(struct nl_sock *sk, struct nl_msg *msg)
{
struct nlmsghdr *nlh;
nlh = nlmsg_hdr(msg);
if (nlh->nlmsg_pid == NL_AUTO_PORT)
nlh->nlmsg_pid = nl_socket_get_local_port(sk);
if (nlh->nlmsg_seq == NL_AUTO_SEQ)
nlh->nlmsg_seq = sk->s_seq_next++;
if (msg->nm_protocol == -1)
msg->nm_protocol = sk->s_proto;
nlh->nlmsg_flags |= NLM_F_REQUEST;
if (!(sk->s_flags & NL_NO_AUTO_ACK))
nlh->nlmsg_flags |= NLM_F_ACK;
}
int
nl_send(struct nl_sock *sk, struct nl_msg *msg)
{
struct iovec iov = {
.iov_base = (void *) nlmsg_hdr(msg),
.iov_len = nlmsg_hdr(msg)->nlmsg_len,
};
return nl_send_iovec(sk, msg, &iov, 1);
}
int
nl_send_auto(struct nl_sock *sk, struct nl_msg *msg)
{
nl_complete_msg(sk, msg);
return nl_send(sk, msg);
}
int
nl_recv(struct nl_sock * sk,
struct sockaddr_nl *nla,
unsigned char ** buf,
struct ucred * out_creds,
gboolean * out_creds_has)
{
ssize_t n;
int flags = 0;
struct iovec iov;
struct msghdr msg = {
.msg_name = (void *) nla,
.msg_namelen = sizeof(struct sockaddr_nl),
.msg_iov = &iov,
.msg_iovlen = 1,
};
struct ucred tmpcreds;
gboolean tmpcreds_has = FALSE;
int retval;
int errsv;
nm_assert(nla);
nm_assert(buf && !*buf);
nm_assert(!out_creds_has == !out_creds);
if ((sk->s_flags & NL_MSG_PEEK)
|| (!(sk->s_flags & NL_MSG_PEEK_EXPLICIT) && sk->s_bufsize == 0))
flags |= MSG_PEEK | MSG_TRUNC;
iov.iov_len = sk->s_bufsize ?: (((size_t) nm_utils_getpagesize()) * 4u);
iov.iov_base = g_malloc(iov.iov_len);
if (out_creds && (sk->s_flags & NL_SOCK_PASSCRED)) {
msg.msg_controllen = CMSG_SPACE(sizeof(struct ucred));
msg.msg_control = g_malloc(msg.msg_controllen);
}
retry:
n = recvmsg(sk->s_fd, &msg, flags);
if (!n) {
retval = 0;
goto abort;
}
if (n < 0) {
errsv = errno;
if (errsv == EINTR)
goto retry;
retval = -nm_errno_from_native(errsv);
goto abort;
}
if (msg.msg_flags & MSG_CTRUNC) {
if (msg.msg_controllen == 0) {
retval = -NME_NL_MSG_TRUNC;
goto abort;
}
msg.msg_controllen *= 2;
msg.msg_control = g_realloc(msg.msg_control, msg.msg_controllen);
goto retry;
}
if (iov.iov_len < n || (msg.msg_flags & MSG_TRUNC)) {
/* respond with error to an incomplete message */
if (flags == 0) {
retval = -NME_NL_MSG_TRUNC;
goto abort;
}
/* Provided buffer is not long enough, enlarge it
* to size of n (which should be total length of the message)
* and try again. */
iov.iov_base = g_realloc(iov.iov_base, n);
iov.iov_len = n;
flags = 0;
goto retry;
}
if (flags != 0) {
/* Buffer is big enough, do the actual reading */
flags = 0;
goto retry;
}
if (msg.msg_namelen != sizeof(struct sockaddr_nl)) {
retval = -NME_UNSPEC;
goto abort;
}
if (out_creds && (sk->s_flags & NL_SOCK_PASSCRED)) {
struct cmsghdr *cmsg;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level != SOL_SOCKET)
continue;
if (cmsg->cmsg_type != SCM_CREDENTIALS)
continue;
memcpy(&tmpcreds, CMSG_DATA(cmsg), sizeof(tmpcreds));
tmpcreds_has = TRUE;
break;
}
}
retval = n;
abort:
g_free(msg.msg_control);
if (retval <= 0) {
g_free(iov.iov_base);
return retval;
}
*buf = iov.iov_base;
if (out_creds && tmpcreds_has)
*out_creds = tmpcreds;
NM_SET_OUT(out_creds_has, tmpcreds_has);
return retval;
}
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