utils: add example usage of nfq_get_uid and nfq_get_gid

[ Mangled this patch to indicate that this kernel does not support
  UID/GID retrieval not to confuse users --pablo ]

Signed-off-by: Valentina Giusti <Valentina.Giusti@bmw-carit.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/utils/nfqnl_test.c b/utils/nfqnl_test.c
index a554f2d..34cb113 100644 (file)
--- a/utils/nfqnl_test.c
+++ b/utils/nfqnl_test.c
@@ -15,7 +15,7 @@ static u_int32_t print_pkt (struct nfq_data *tb)
        int id = 0;
        struct nfqnl_msg_packet_hdr *ph;
        struct nfqnl_msg_packet_hw *hwph;
-       u_int32_t mark,ifi; 
+       u_int32_t mark, ifi, uid, gid;
        int ret;
        unsigned char *data;
 
@@ -55,6 +55,12 @@ static u_int32_t print_pkt (struct nfq_data *tb)
        if (ifi)
                printf("physoutdev=%u ", ifi);
 
+       if (nfq_get_uid(tb, &uid))
+               printf("uid=%u ", uid);
+
+       if (nfq_get_gid(tb, &gid))
+               printf("gid=%u ", gid);
+
        ret = nfq_get_payload(tb, &data);
        if (ret >= 0)
                printf("payload_len=%d ", ret);
@@ -114,6 +120,14 @@ int main(int argc, char **argv)
                exit(1);
        }
 
+       printf("setting flags to request UID and GID\n");
+       if (nfq_set_queue_flags(qh, NFQA_CFG_F_UID_GID, NFQA_CFG_F_UID_GID)) {
+               fprintf(stderr, "This kernel version does not allow to "
+                               "retrieve process UID/GID.\n");
+       }
+
+       printf("Waiting for packets...\n");
+
        fd = nfq_fd(h);
 
        for (;;) {