void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
const void *data)
{
struct nfattr *nfa;
int size = NFA_LENGTH(attrlen);
nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
nfa->nfa_type = attrtype;
nfa->nfa_len = size;
memcpy(NFA_DATA(nfa), data, attrlen);
memset(NFA_DATA(nfa) + attrlen, 0, NFA_ALIGN(size) - size);
}
/**
* nfnl_nfa_addattr_l - Add variable length attribute to struct nfattr
*
* @nfa: struct nfattr
* @maxlen: maximal length of nfattr buffer
* @type: type for new attribute
* @data: content of new attribute
* @alen: length of new attribute
*
*/
int nfnl_nfa_addattr_l(struct nfattr *nfa, int maxlen, int type,
const void *data, int alen)
{
struct nfattr *subnfa;
int len = NFA_LENGTH(alen);
assert(nfa);
assert(maxlen > 0);
assert(type >= 0);
if (NFA_ALIGN(nfa->nfa_len) + len > maxlen) {
errno = ENOSPC;
return -1;
}
subnfa = (struct nfattr *)(((char *)nfa) + NFA_ALIGN(nfa->nfa_len));
subnfa->nfa_type = type;
subnfa->nfa_len = len;
memcpy(NFA_DATA(subnfa), data, alen);
nfa->nfa_len = NFA_ALIGN(nfa->nfa_len) + len;
return 0;
}
/**
* nfnl_build_nfa_iovec - Build two iovec's from tag, length and value
*
* @iov: pointer to array of two 'struct iovec' (caller-allocated)
* @nfa: pointer to 'struct nfattr' (caller-allocated)
* @type: type (tag) of attribute
* @len: length of value
* @val: pointer to buffer containing 'value'
*
*/
void nfnl_build_nfa_iovec(struct iovec *iov, struct nfattr *nfa,
uint16_t type, uint32_t len, unsigned char *val)
{
assert(iov);
assert(nfa);
/* Set the attribut values */
nfa->nfa_len = sizeof(struct nfattr) + len;
nfa->nfa_type = type;
iov[0].iov_base = nfa;
iov[0].iov_len = sizeof(*nfa);
iov[1].iov_base = val;
iov[1].iov_len = NFA_ALIGN(len);
}
/**
* nfnl_addattr_l - Add variable length attribute to nlmsghdr
* @n: netlink message header to which attribute is to be added
* @maxlen: maximum length of netlink message header
* @type: type of new attribute
* @data: content of new attribute
* @len: attribute length
*/
int nfnl_addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
int alen)
{
int len = NFA_LENGTH(alen);
struct nfattr *nfa;
assert(n);
assert(maxlen > 0);
assert(type >= 0);
if ((NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
errno = ENOSPC;
return -1;
}
nfa = NLMSG_TAIL(n);
nfa->nfa_type = type;
nfa->nfa_len = len;
memcpy(NFA_DATA(nfa), data, alen);
n->nlmsg_len = (NLMSG_ALIGN(n->nlmsg_len) + NFA_ALIGN(len));
return 0;
}
/**
* nfnl_listen: listen for one or more netlink messages
* @nfnhl: libnfnetlink handle
* @handler: callback function to be called for every netlink message
* - the callback handler should normally return 0
* - but may return a negative error code which will cause
* nfnl_listen to return immediately with the same error code
* - or return a postivie error code which will cause
* nfnl_listen to return after it has finished processing all
* the netlink messages in the current packet
* Thus a positive error code will terminate nfnl_listen "soon"
* without any loss of data, a negative error code will terminate
* nfnl_listen "very soon" and throw away data already read from
* the netlink socket.
* @jarg: opaque argument passed on to callback
*
* This function is used to receive and process messages coming from an open
* nfnetlink handler like events or information request via nfnl_send().
*
* On error, -1 is returned, unfortunately errno is not always set
* appropiately. For that reason, the use of this function is DEPRECATED.
* Please, use nfnl_receive_process() instead.
*/
int nfnl_listen(struct nfnl_handle *nfnlh,
int (*handler)(struct sockaddr_nl *, struct nlmsghdr *n,
void *), void *jarg)
{
struct sockaddr_nl nladdr;
char buf[NFNL_BUFFSIZE] __attribute__ ((aligned));
struct iovec iov;
int remain;
struct nlmsghdr *h;
struct nlmsgerr *msgerr;
int quit=0;
struct msghdr msg = {
.msg_name = &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1,
};
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
while (! quit) {
remain = recvmsg(nfnlh->fd, &msg, 0);
if (remain < 0) {
if (errno == EINTR)
continue;
/* Bad file descriptor */
else if (errno == EBADF)
break;
else if (errno == EAGAIN)
break;
nfnl_error("recvmsg overrun: %s", strerror(errno));
continue;
}
if (remain == 0) {
nfnl_error("EOF on netlink");
return -1;
}
if (msg.msg_namelen != sizeof(nladdr)) {
nfnl_error("Bad sender address len (%d)",
msg.msg_namelen);
return -1;
}
for (h = (struct nlmsghdr *)buf; remain >= sizeof(*h);) {
int err;
int len = h->nlmsg_len;
int l = len - sizeof(*h);
if (l < 0 || len > remain) {
if (msg.msg_flags & MSG_TRUNC) {
nfnl_error("MSG_TRUNC");
return -1;
}
nfnl_error("Malformed msg (len=%d)", len);
return -1;
}
/* end of messages reached, let's return */
if (h->nlmsg_type == NLMSG_DONE)
return 0;
/* Break the loop if success is explicitely
* reported via NLM_F_ACK flag set */
if (h->nlmsg_type == NLMSG_ERROR) {
msgerr = NLMSG_DATA(h);
return msgerr->error;
}
err = handler(&nladdr, h, jarg);
if (err < 0)
return err;
quit |= err;
/* FIXME: why not _NEXT macros, etc.? */
//h = NLMSG_NEXT(h, remain);
remain -= NLMSG_ALIGN(len);
h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
}
if (msg.msg_flags & MSG_TRUNC) {
nfnl_error("MSG_TRUNC");
continue;
}
if (remain) {
nfnl_error("remnant size %d", remain);
return -1;
}
}
return quit;
}
/**
* nfnl_talk - send a request and then receive and process messages returned
* @nfnlh: nfnetelink handler
* @n: netlink message that contains the request
* @peer: peer PID
* @groups: netlink groups
* @junk: callback called if out-of-sequence messages were received
* @jarg: data for the junk callback
*
* This function is used to request an action that does not returns any
* information. On error, a negative value is returned, errno could be
* set appropiately. For that reason, the use of this function is DEPRECATED.
* Please, use nfnl_query() instead.
*/
int nfnl_talk(struct nfnl_handle *nfnlh, struct nlmsghdr *n, pid_t peer,
unsigned groups, struct nlmsghdr *answer,
int (*junk)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
void *jarg)
{
char buf[NFNL_BUFFSIZE] __attribute__ ((aligned));
struct sockaddr_nl nladdr;
struct nlmsghdr *h;
unsigned int seq;
int status;
struct iovec iov = {
n, n->nlmsg_len
};
struct msghdr msg = {
.msg_name = &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1,
};
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_pid = peer;
nladdr.nl_groups = groups;
n->nlmsg_seq = seq = ++nfnlh->seq;
/* FIXME: why ? */
if (!answer)
n->nlmsg_flags |= NLM_F_ACK;
status = sendmsg(nfnlh->fd, &msg, 0);
if (status < 0) {
nfnl_error("sendmsg(netlink) %s", strerror(errno));
return -1;
}
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
while (1) {
status = recvmsg(nfnlh->fd, &msg, 0);
if (status < 0) {
if (errno == EINTR)
continue;
nfnl_error("recvmsg over-run");
continue;
}
if (status == 0) {
nfnl_error("EOF on netlink");
return -1;
}
if (msg.msg_namelen != sizeof(nladdr)) {
nfnl_error("Bad sender address len %d",
msg.msg_namelen);
return -1;
}
for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
int len = h->nlmsg_len;
int l = len - sizeof(*h);
int err;
if (l < 0 || len > status) {
if (msg.msg_flags & MSG_TRUNC) {
nfnl_error("Truncated message\n");
return -1;
}
nfnl_error("Malformed message: len=%d\n", len);
return -1; /* FIXME: libnetlink exits here */
}
if (h->nlmsg_pid != nfnlh->local.nl_pid ||
h->nlmsg_seq != seq) {
if (junk) {
err = junk(&nladdr, h, jarg);
if (err < 0)
return err;
}
goto cont;
}
if (h->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *err = NLMSG_DATA(h);
if (l < sizeof(struct nlmsgerr))
nfnl_error("ERROR truncated\n");
else {
errno = -err->error;
if (errno == 0) {
if (answer)
memcpy(answer, h, h->nlmsg_len);
return 0;
}
perror("NFNETLINK answers");
}
return err->error;
}
if (answer) {
memcpy(answer, h, h->nlmsg_len);
return 0;
}
nfnl_error("Unexpected reply!\n");
cont:
status -= NLMSG_ALIGN(len);
h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
}
if (msg.msg_flags & MSG_TRUNC) {
nfnl_error("Messages truncated\n");
continue;
}
if (status)
nfnl_error("Remnant of size %d\n", status);
}
}
/**
* nfnl_addattr_l - Add variable length attribute to nlmsghdr
* @n: netlink message header to which attribute is to be added
* @maxlen: maximum length of netlink message header
* @type: type of new attribute
* @data: content of new attribute
* @len: attribute length
*/
int nfnl_addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
int alen)
{
int len = NFA_LENGTH(alen);
struct nfattr *nfa;
assert(n);
assert(maxlen > 0);
assert(type >= 0);
if ((NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
errno = ENOSPC;
return -1;
}
nfa = NLMSG_TAIL(n);
nfa->nfa_type = type;
nfa->nfa_len = len;
memcpy(NFA_DATA(nfa), data, alen);
memset((uint8_t *)nfa + nfa->nfa_len, 0, NFA_ALIGN(alen) - alen);
n->nlmsg_len = (NLMSG_ALIGN(n->nlmsg_len) + NFA_ALIGN(len));
return 0;
}
/* This is an inline function, we don't really care about a long
* list of arguments */
static inline int
__build_packet_message(struct nfulnl_instance *inst,
const struct sk_buff *skb,
unsigned int data_len,
unsigned int pf,
unsigned int hooknum,
const struct net_device *indev,
const struct net_device *outdev,
const struct nf_loginfo *li,
const char *prefix)
{
unsigned char *old_tail;
struct nfulnl_msg_packet_hdr pmsg;
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
u_int32_t tmp_uint;
UDEBUG("entered\n");
old_tail = inst->skb->tail;
nlh = NLMSG_PUT(inst->skb, 0, 0,
NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
sizeof(struct nfgenmsg));
nfmsg = NLMSG_DATA(nlh);
nfmsg->nfgen_family = pf;
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = htons(inst->group_num);
pmsg.hw_protocol = htons(skb->protocol);
pmsg.hook = hooknum;
NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
if (prefix) {
int slen = strlen(prefix);
if (slen > NFULNL_PREFIXLEN)
slen = NFULNL_PREFIXLEN;
NFA_PUT(inst->skb, NFULA_PREFIX, slen, prefix);
}
if (indev) {
tmp_uint = htonl(indev->ifindex);
#ifndef CONFIG_BRIDGE_NETFILTER
NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
&tmp_uint);
#else
if (pf == PF_BRIDGE) {
/* Case 1: outdev is physical input device, we need to
* look for bridge group (when called from
* netfilter_bridge) */
NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
sizeof(tmp_uint), &tmp_uint);
/* this is the bridge group "brX" */
tmp_uint = htonl(indev->br_port->br->dev->ifindex);
NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
sizeof(tmp_uint), &tmp_uint);
} else {
/* Case 2: indev is bridge group, we need to look for
* physical device (when called from ipv4) */
NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
sizeof(tmp_uint), &tmp_uint);
if (skb->nf_bridge && skb->nf_bridge->physindev) {
tmp_uint =
htonl(skb->nf_bridge->physindev->ifindex);
NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
sizeof(tmp_uint), &tmp_uint);
}
}
#endif
}
if (outdev) {
tmp_uint = htonl(outdev->ifindex);
#ifndef CONFIG_BRIDGE_NETFILTER
NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
&tmp_uint);
#else
if (pf == PF_BRIDGE) {
/* Case 1: outdev is physical output device, we need to
* look for bridge group (when called from
* netfilter_bridge) */
NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
sizeof(tmp_uint), &tmp_uint);
/* this is the bridge group "brX" */
tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
sizeof(tmp_uint), &tmp_uint);
} else {
/* Case 2: indev is a bridge group, we need to look
* for physical device (when called from ipv4) */
NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
sizeof(tmp_uint), &tmp_uint);
if (skb->nf_bridge) {
tmp_uint =
htonl(skb->nf_bridge->physoutdev->ifindex);
NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
sizeof(tmp_uint), &tmp_uint);
}
}
#endif
}
if (skb->nfmark) {
tmp_uint = htonl(skb->nfmark);
NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
}
if (indev && skb->dev && skb->dev->hard_header_parse) {
struct nfulnl_msg_packet_hw phw;
phw.hw_addrlen =
skb->dev->hard_header_parse((struct sk_buff *)skb,
phw.hw_addr);
phw.hw_addrlen = htons(phw.hw_addrlen);
NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
}
if (skb->tstamp.off_sec) {
struct nfulnl_msg_packet_timestamp ts;
ts.sec = cpu_to_be64(skb->tstamp.off_sec);
ts.usec = cpu_to_be64(skb->tstamp.off_usec);
NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
}
/* UID */
if (skb->sk) {
read_lock_bh(&skb->sk->sk_callback_lock);
if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
u_int32_t uid = htonl(skb->sk->sk_socket->file->f_uid);
/* need to unlock here since NFA_PUT may goto */
read_unlock_bh(&skb->sk->sk_callback_lock);
NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
} else
read_unlock_bh(&skb->sk->sk_callback_lock);
}
/* local sequence number */
if (inst->flags & NFULNL_CFG_F_SEQ) {
tmp_uint = htonl(inst->seq++);
NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
}
/* global sequence number */
if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
tmp_uint = atomic_inc_return(&global_seq);
NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
}
if (data_len) {
struct nfattr *nfa;
int size = NFA_LENGTH(data_len);
if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
goto nlmsg_failure;
}
nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
nfa->nfa_type = NFULA_PAYLOAD;
nfa->nfa_len = size;
if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
BUG();
}
nlh->nlmsg_len = inst->skb->tail - old_tail;
return 0;
nlmsg_failure:
UDEBUG("nlmsg_failure\n");
nfattr_failure:
PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
return -1;
}