svn commit: r343756 - stable/12/sys/netinet

[Brooks Davis]

Author: brooks
Date: Mon Feb  4 22:38:34 2019
New Revision: 343756
URL: https://svnweb.freebsd.org/changeset/base/343756

Log:
  MFC r343587:
  
  Add a simple port filter to SIFTR.
  
  SIFTR does not allow any kind of filtering, but captures every packet
  processed by the TCP stack.
  Often, only a specific session or service is of interest, and doing the
  filtering in post-processing of the log adds to the overhead of SIFTR.
  
  This adds a new sysctl net.inet.siftr.port_filter. When set to zero, all
  packets get captured as previously. If set to any other value, only
  packets where either the source or the destination ports match, are
  captured in the log file.
  
  Submitted by:	Richard Scheffenegger
  Reviewed by:	Cheng Cui
  Differential Revision:	https://reviews.freebsd.org/D18897

Modified:
  stable/12/sys/netinet/siftr.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/netinet/siftr.c
==============================================================================
--- stable/12/sys/netinet/siftr.c	Mon Feb  4 21:28:25 2019	(r343755)
+++ stable/12/sys/netinet/siftr.c	Mon Feb  4 22:38:34 2019	(r343756)
@@ -272,6 +272,7 @@ static volatile unsigned int siftr_exit_pkt_manager_th
 static unsigned int siftr_enabled = 0;
 static unsigned int siftr_pkts_per_log = 1;
 static unsigned int siftr_generate_hashes = 0;
+static uint16_t     siftr_port_filter = 0;
 /* static unsigned int siftr_binary_log = 0; */
 static char siftr_logfile[PATH_MAX] = "/var/log/siftr.log";
 static char siftr_logfile_shadow[PATH_MAX] = "/var/log/siftr.log";
@@ -317,6 +318,10 @@ SYSCTL_UINT(_net_inet_siftr, OID_AUTO, genhashes, CTLF
     &siftr_generate_hashes, 0,
     "enable packet hash generation");
 
+SYSCTL_U16(_net_inet_siftr, OID_AUTO, port_filter, CTLFLAG_RW,
+    &siftr_port_filter, 0,
+    "enable packet filter on a TCP port");
+
 /* XXX: TODO
 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, binary, CTLFLAG_RW,
     &siftr_binary_log, 0,
@@ -907,6 +912,16 @@ siftr_chkpkt(void *arg, struct mbuf **m, struct ifnet 
 		goto inp_unlock;
 	}
 
+	/*
+	 * Only pkts selected by the tcp port filter
+	 * can be inserted into the pkt_queue
+	 */
+	if ((siftr_port_filter != 0) && 
+	    (siftr_port_filter != ntohs(inp->inp_lport)) &&
+	    (siftr_port_filter != ntohs(inp->inp_fport))) {
+		goto inp_unlock;
+	}
+
 	pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
 
 	if (pn == NULL) {
@@ -1080,6 +1095,16 @@ siftr_chkpkt6(void *arg, struct mbuf **m, struct ifnet
 		else
 			ss->nskip_out_tcpcb++;
 
+		goto inp_unlock6;
+	}
+
+	/*
+	 * Only pkts selected by the tcp port filter
+	 * can be inserted into the pkt_queue
+	 */
+	if ((siftr_port_filter != 0) && 
+	    (siftr_port_filter != ntohs(inp->inp_lport)) &&
+	    (siftr_port_filter != ntohs(inp->inp_fport))) {
 		goto inp_unlock6;
 	}