xnu-4903.270.47.tar.gz

[apple/xnu.git] / bsd / man / man4 / icmp.4

diff --git a/bsd/man/man4/icmp.4 b/bsd/man/man4/icmp.4
index 054b770186744f8f63725cb205d999421ad52a90..4013ef69220f474c96ad42a45e8f7e1389eee885 100644 (file)
--- a/bsd/man/man4/icmp.4
+++ b/bsd/man/man4/icmp.4
@@ -87,6 +87,9 @@ them (based on the destination address).
 Incoming packets are received with the
 .Tn IP
 header and options intact.
+Note that the ip_off and ip_len fields are in host byte order.
+For more information about the IP header structure, see 
+.Xr ip 4 .
 .Ss "Non-privileged ICMP"
 .Pp
 .Tn ICMP
@@ -94,14 +97,7 @@ sockets can be opened with the
 .Dv SOCK_DGRAM
 socket type without requiring root privileges. The synopsis is the following:
 .Pp
-.Fn socket AF_INET SOCK_DGRAM IPPROTO_IP
-.Pp
-This can be used by non root privileged processes to send 
-.Tn ICMP
-echo requests to gauge the quality of the connectivity to a host, to receive 
-.Tn ICMP
-destination unreachable message for path MTU discovery, or to receveive 
-time exceeded message for traceroute.
+.Fn socket AF_INET SOCK_DGRAM IPPROTO_ICMP
 .Pp
 Datagram oriented
 .Tn ICMP
@@ -116,6 +112,16 @@ The minimal length of an
 .Tn ICMP 
 message request is eight (8) octets.
 .Pp
+The advantage of using datagram oriented
+.Tn ICMP
+sockets is that even a non-privileged process can use 
+.Tn ICMP
+echo requests to gauge the quality of the connectivity to a host, 
+or to receive 
+.Tn ICMP
+destination unreachable message for path MTU discovery, or to receive 
+time exceeded messages for traceroute. 
+.Pp
 The following 
 .Tn IP
 level option can be used with datagram oriented 
@@ -195,10 +201,10 @@ or
 header.
 .El
 .Sh SEE ALSO
-.Xr send 2 ,
 .Xr recv 2 ,
-.Xr intro 4 ,
+.Xr send 2 ,
 .Xr inet 4 ,
+.Xr intro 4 ,
 .Xr ip 4
 .Sh HISTORY
 The