From 49dc2251d8d7098b09a4b5a36dafdbd93568f2fc Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 23 Nov 2012 12:10:10 +0100 Subject: examples: nf-queue: fix api usage 1. struct nlattr *attr[NFQA_MAX+1] must be initialized. Otherwise, attr[FOO] might be non-null after parsing even if that attribute isn't present in the message. 2. mnl_attr_get_payload will never return NULL (if the attribute is NULL, it returns MNL_ATTR_HDRLEN.) Signed-off-by: Florian Westphal --- examples/nf-queue.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/examples/nf-queue.c b/examples/nf-queue.c index 4d56751..7adac21 100644 --- a/examples/nf-queue.c +++ b/examples/nf-queue.c @@ -31,12 +31,11 @@ nfq_hdr_put(char *buf, int type, uint32_t queue_num) return nlh; } -static int +static void nfq_send_verdict(int queue_num, uint32_t id) { char buf[MNL_SOCKET_BUFFER_SIZE]; struct nlmsghdr *nlh; - int ret; nlh = nfq_hdr_put(buf, NFQNL_MSG_VERDICT, queue_num); nfq_nlmsg_verdict_put(nlh, id, NF_ACCEPT); @@ -45,16 +44,15 @@ nfq_send_verdict(int queue_num, uint32_t id) perror("mnl_socket_send"); exit(EXIT_FAILURE); } - - return ret; } static int queue_cb(const struct nlmsghdr *nlh, void *data) { struct nfqnl_msg_packet_hdr *ph = NULL; - struct nlattr *attr[NFQA_MAX+1]; + struct nlattr *attr[NFQA_MAX+1] = {}; uint32_t id = 0; struct nfgenmsg *nfg; + uint16_t plen; if (nfq_nlmsg_parse(nlh, attr) < 0) { perror("problems parsing"); @@ -63,17 +61,19 @@ static int queue_cb(const struct nlmsghdr *nlh, void *data) nfg = mnl_nlmsg_get_payload(nlh); - ph = (struct nfqnl_msg_packet_hdr *) - mnl_attr_get_payload(attr[NFQA_PACKET_HDR]); - if (ph == NULL) { - perror("problems retrieving metaheader"); + if (attr[NFQA_PACKET_HDR] == NULL) { + fputs("metaheader not set\n", stderr); return MNL_CB_ERROR; } - id = ntohl(ph->packet_id); + ph = mnl_attr_get_payload(attr[NFQA_PACKET_HDR]); - printf("packet received (id=%u hw=0x%04x hook=%u)\n", - id, ntohs(ph->hw_protocol), ph->hook); + plen = mnl_attr_get_payload_len(attr[NFQA_PAYLOAD]); + /* void *payload = mnl_attr_get_payload(attr[NFQA_PAYLOAD]); */ + + id = ntohl(ph->packet_id); + printf("packet received (id=%u hw=0x%04x hook=%u, payload len %u)\n", + id, ntohs(ph->hw_protocol), ph->hook, plen); nfq_send_verdict(ntohs(nfg->res_id), id); -- cgit v1.2.3