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Add missing dtrace probes for received UDP packets.

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Fire UDP receive probes when a packet is received and there is no
endpoint consuming it. Fire the probe also if the TTL of the
received packet is smaller than the minimum required by the endpoint.

Clarify also in the man page, when the probe fires.

Reviewed by:		dteske@, markj@, rrs@
Sponsored by:		Netflix, Inc.
Differential Revision:	https://reviews.freebsd.org/D16046
This commit is contained in:
Michael Tuexen 2018-07-20 15:32:20 +00:00
parent 39ebf76745
commit e1526d5a5b
3 changed files with 9 additions and 2 deletions
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8
share/man/man4/dtrace_udp.4
View File

@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd April 18, 2015
.Dd July 20, 2018
.Dt DTRACE_UDP 4
.Os
.Sh NAME
@ -45,7 +45,11 @@ The
.Fn udp:::send
probe fires whenever the kernel prepares to transmit a UDP packet, and the
.Fn udp:::receive
probe fires whenever the kernel receives a UDP packet.
probe fires whenever the kernel receives a UDP packet, unless
the UDP header is incomplete,
the destination port is 0,
the length field is invalid,
or the checksum is wrong.
The arguments to these probes can be used to obtain detailed information about
the IP and UDP headers of the corresponding packet.
.Sh ARGUMENTS

2
sys/netinet/udp_usrreq.c
View File

@ -685,6 +685,7 @@ udp_input(struct mbuf **mp, int *offp, int proto)
inet_ntoa_r(ip->ip_dst, dst), ntohs(uh->uh_dport),
inet_ntoa_r(ip->ip_src, src), ntohs(uh->uh_sport));
}
UDP_PROBE(receive, NULL, NULL, ip, NULL, uh);
UDPSTAT_INC(udps_noport);
if (m->m_flags & (M_BCAST | M_MCAST)) {
UDPSTAT_INC(udps_noportbcast);
@ -704,6 +705,7 @@ udp_input(struct mbuf **mp, int *offp, int proto)
*/
INP_RLOCK_ASSERT(inp);
if (inp->inp_ip_minttl && inp->inp_ip_minttl > ip->ip_ttl) {
UDP_PROBE(receive, NULL, inp, ip, inp, uh);
INP_RUNLOCK(inp);
m_freem(m);
return (IPPROTO_DONE);

1
sys/netinet6/udp6_usrreq.c
View File

@ -483,6 +483,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
ip6_sprintf(ip6bufs, &ip6->ip6_src),
ntohs(uh->uh_sport));
}
UDP_PROBE(receive, NULL, NULL, ip6, NULL, uh);
UDPSTAT_INC(udps_noport);
if (m->m_flags & M_MCAST) {
printf("UDP6: M_MCAST is set in a unicast packet.\n");