Messages in this thread | | | Date | Thu, 18 Dec 2014 15:13:59 -0700 | From | David Ahern <> | Subject | Re: [PATCH] tools lib traceevent: Add support for IP address formats |
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On 12/18/14 2:45 PM, Valdis.Kletnieks@vt.edu wrote: > On Thu, 18 Dec 2014 08:10:43 -0700, David Ahern said: >> Adds helper for following kernel formats: >> %pi4 print an IPv4 address with leading zeros >> %pI4 print an IPv4 address without leading zeros >> %pi6 print an IPv6 address without colons >> %pI6 print an IPv6 address with colons >> %pI6c print an IPv6 address with colons >> %pISpc print an IP address from a sockaddr > > The description for %pI6C in the changelog doesn't match the code: > >> + * %pI6c print an IPv6 address in compressed form with colons > > Threw me for a loop for a while trying to figure out how pI6 and pI6c were > different, till I read the code... >
Per Documentation/printk-formats.txt:
%pI6 0001:0002:0003:0004:0005:0006:0007:0008 %pi6 00010002000300040005000600070008 %pI6c 1:2:3:4:5:6:7:8
For printing IPv6 network-order 16-bit hex addresses. The 'I6' and 'i6' specifiers result in a printed address with ('I6') or without ('i6') colon-separators. Leading zeros are always used.
The additional 'c' specifier can be used with the 'I' specifier to print a compressed IPv6 address as described by http://tools.ietf.org/html/rfc5952
I do see two mistakes in my patch -- use of 'c' and 'S' requires 'I'. After that the code that prints pI6c is a slightly modified version of what is in lib/vsprintf.c so the output between in-kernel tracing (cat trace_pipe) should match perf-script output. Compare ip6_compressed_string() in lib/vsprintf.c to print_ip6c_addr() in this patch.
Are you seeing something different?
David
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