Use union of char buffer and message header to ensure proper byte
alignment.
This patch increases portability, but alignment is still not respected
in nflog_get_*() which still leaves libnetfilter_log unusable on
particular platforms.
Signed-off-by: Fabian Hugelshofer <hugelshofer2006@xxxxxx>
diff --git a/src/libnetfilter_log.c b/src/libnetfilter_log.c
index a3bd435..2019b0c 100644
--- a/src/libnetfilter_log.c
+++ b/src/libnetfilter_log.c
@@ -106,18 +106,20 @@ static int
__build_send_cfg_msg(struct nflog_handle *h, u_int8_t command,
u_int16_t queuenum, u_int8_t pf)
{
- char buf[NFNL_HEADER_LEN
- +NFA_LENGTH(sizeof(struct nfulnl_msg_config_cmd))];
+ union {
+ char buf[NFNL_HEADER_LEN
+ +NFA_LENGTH(sizeof(struct nfulnl_msg_config_cmd))];
+ struct nlmsghdr nmh;
+ } u;
struct nfulnl_msg_config_cmd cmd;
- struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
- nfnl_fill_hdr(h->nfnlssh, nmh, 0, pf, queuenum,
+ nfnl_fill_hdr(h->nfnlssh, &u.nmh, 0, pf, queuenum,
NFULNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
cmd.command = command;
- nfnl_addattr_l(nmh, sizeof(buf), NFULA_CFG_CMD, &cmd, sizeof(cmd));
+ nfnl_addattr_l(&u.nmh, sizeof(u), NFULA_CFG_CMD, &cmd, sizeof(cmd));
- return nfnl_talk(h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
+ return nfnl_talk(h->nfnlh, &u.nmh, 0, 0, NULL, NULL, NULL);
}
static int __nflog_rcv_pkt(struct nlmsghdr *nlh, struct nfattr *nfa[],
@@ -291,60 +293,68 @@ int nflog_unbind_group(struct nflog_g_handle *gh)
int nflog_set_mode(struct nflog_g_handle *gh,
u_int8_t mode, u_int32_t range)
{
- char buf[NFNL_HEADER_LEN
- +NFA_LENGTH(sizeof(struct nfulnl_msg_config_mode))];
+ union {
+ char buf[NFNL_HEADER_LEN
+ +NFA_LENGTH(sizeof(struct nfulnl_msg_config_mode))];
+ struct nlmsghdr nmh;
+ } u;
struct nfulnl_msg_config_mode params;
- struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
- nfnl_fill_hdr(gh->h->nfnlssh, nmh, 0, AF_UNSPEC, gh->id,
+ nfnl_fill_hdr(gh->h->nfnlssh, &u.nmh, 0, AF_UNSPEC, gh->id,
NFULNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
params.copy_range = htonl(range); /* copy_range is short */
params.copy_mode = mode;
- nfnl_addattr_l(nmh, sizeof(buf), NFULA_CFG_MODE, ¶ms,
+ nfnl_addattr_l(&u.nmh, sizeof(u), NFULA_CFG_MODE, ¶ms,
sizeof(params));
- return nfnl_talk(gh->h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
+ return nfnl_talk(gh->h->nfnlh, &u.nmh, 0, 0, NULL, NULL, NULL);
}
int nflog_set_timeout(struct nflog_g_handle *gh, u_int32_t timeout)
{
- char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int32_t))];
- struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
+ union {
+ char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int32_t))];
+ struct nlmsghdr nmh;
+ } u;
- nfnl_fill_hdr(gh->h->nfnlssh, nmh, 0, AF_UNSPEC, gh->id,
+ nfnl_fill_hdr(gh->h->nfnlssh, &u.nmh, 0, AF_UNSPEC, gh->id,
NFULNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
- nfnl_addattr32(nmh, sizeof(buf), NFULA_CFG_TIMEOUT, htonl(timeout));
+ nfnl_addattr32(&u.nmh, sizeof(u), NFULA_CFG_TIMEOUT, htonl(timeout));
- return nfnl_talk(gh->h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
+ return nfnl_talk(gh->h->nfnlh, &u.nmh, 0, 0, NULL, NULL, NULL);
}
int nflog_set_qthresh(struct nflog_g_handle *gh, u_int32_t qthresh)
{
- char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int32_t))];
- struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
+ union {
+ char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int32_t))];
+ struct nlmsghdr nmh;
+ } u;
- nfnl_fill_hdr(gh->h->nfnlssh, nmh, 0, AF_UNSPEC, gh->id,
+ nfnl_fill_hdr(gh->h->nfnlssh, &u.nmh, 0, AF_UNSPEC, gh->id,
NFULNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
- nfnl_addattr32(nmh, sizeof(buf), NFULA_CFG_QTHRESH, htonl(qthresh));
+ nfnl_addattr32(&u.nmh, sizeof(u), NFULA_CFG_QTHRESH, htonl(qthresh));
- return nfnl_talk(gh->h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
+ return nfnl_talk(gh->h->nfnlh, &u.nmh, 0, 0, NULL, NULL, NULL);
}
int nflog_set_nlbufsiz(struct nflog_g_handle *gh, u_int32_t nlbufsiz)
{
- char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int32_t))];
- struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
+ union {
+ char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int32_t))];
+ struct nlmsghdr nmh;
+ } u;
int status;
- nfnl_fill_hdr(gh->h->nfnlssh, nmh, 0, AF_UNSPEC, gh->id,
+ nfnl_fill_hdr(gh->h->nfnlssh, &u.nmh, 0, AF_UNSPEC, gh->id,
NFULNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
- nfnl_addattr32(nmh, sizeof(buf), NFULA_CFG_NLBUFSIZ, htonl(nlbufsiz));
+ nfnl_addattr32(&u.nmh, sizeof(u), NFULA_CFG_NLBUFSIZ, htonl(nlbufsiz));
- status = nfnl_talk(gh->h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
+ status = nfnl_talk(gh->h->nfnlh, &u.nmh, 0, 0, NULL, NULL, NULL);
/* we try to have space for at least 10 messages in the socket buffer */
if (status >= 0)
@@ -355,15 +365,17 @@ int nflog_set_nlbufsiz(struct nflog_g_handle *gh, u_int32_t nlbufsiz)
int nflog_set_flags(struct nflog_g_handle *gh, u_int16_t flags)
{
- char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int16_t))];
- struct nlmsghdr *nmh = (struct nlmsghdr *) buf;
+ union {
+ char buf[NFNL_HEADER_LEN+NFA_LENGTH(sizeof(u_int16_t))];
+ struct nlmsghdr nmh;
+ } u;
- nfnl_fill_hdr(gh->h->nfnlssh, nmh, 0, AF_UNSPEC, gh->id,
+ nfnl_fill_hdr(gh->h->nfnlssh, &u.nmh, 0, AF_UNSPEC, gh->id,
NFULNL_MSG_CONFIG, NLM_F_REQUEST|NLM_F_ACK);
- nfnl_addattr16(nmh, sizeof(buf), NFULA_CFG_FLAGS, htons(flags));
+ nfnl_addattr16(&u.nmh, sizeof(u), NFULA_CFG_FLAGS, htons(flags));
- return nfnl_talk(gh->h->nfnlh, nmh, 0, 0, NULL, NULL, NULL);
+ return nfnl_talk(gh->h->nfnlh, &u.nmh, 0, 0, NULL, NULL, NULL);
}
--
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