When the tcp/http actions above were introduced in 1.7-dev4, we used to
proceed like this :
- set-src/set-dst would force the port to zero
- set-src-port/set-dst-port would not do anything if the address family is
neither AF_INET nor AF_INET6.
It was a stupid idea of mine to request this behaviour because it ensures
that these functions cannot be used in a wide number of situations. Because
of the first rule, it is necessary to save the source port one way or
another if only the address has to be changed (so you have to use an
variable). Due to the second rule, there's no way to set the source port
on a unix socket without first overwriting the address. And sometimes it's
really not convenient, especially when there's no way to guarantee that all
fields will properly be set.
In order to fix all this, this small change does the following :
- set-src/set-dst always preserve the original port even if the address
family changes. If the previous address family didn't have a port (eg:
AF_UNIX), then the port is set to zero ;
- set-src-port/set-dst-port always preserve the original address. If the
address doesn't have a port, then the family is forced to IPv4 and the
address to "0.0.0.0".
Thanks to this it now becomes possible to perform one action, the other or
both in any order.
To register a new cli keyword, you need to declare a cli_kw_list
structure in your source file:
static struct cli_kw_list cli_kws = {{ },{
{ { "test", "list", NULL }, "test list : do some tests on the cli", test_parsing, NULL },
{ { NULL }, NULL, NULL, NULL, NULL }
}};
And then register it:
cli_register_kw(&cli_kws);
The first field is an array of 5 elements, where you declare the
keywords combination which will match, it must be ended by a NULL
element.
The second field is used as a usage message, it will appear in the help
of the cli, you can set it to NULL if you don't want to show it, it's a
good idea if you want to overwrite some existing keywords.
The two last fields are callbacks.
The first one is used at parsing time, you can use it to parse the
arguments of your keywords and print small messages. The function must
return 1 in case of a failure, otherwise 0:
#include <proto/dumpstats.h>
static int test_parsing(char **args, struct appctx *appctx)
{
struct chunk out;
if (!*args[2]) {
appctx->ctx.cli.msg = "Error: the 3rd argument is mandatory !";
appctx->st0 = STAT_CLI_PRINT;
return 1;
}
chunk_reset(&trash);
chunk_printf(&trash, "arg[3]: %s\n", args[2]);
chunk_init(&out, NULL, 0);
chunk_dup(&out, &trash);
appctx->ctx.cli.err = out.str;
appctx->st0 = STAT_CLI_PRINT_FREE; /* print and free in the default cli_io_handler */
return 0;
}
The last field is the IO handler callback, it can be set to NULL if you
want to use the default cli_io_handler() otherwise you can write your
own. You can use the private pointer in the appctx if you need to store
a context or some data. stats_dump_sess_to_buffer() is a good example of
IO handler, IO handlers often use the appctx->st2 variable for the state
machine. The handler must return 0 in case it have to be recall later
otherwise 1.
During the stick-table teaching process which occurs at reloading/restart time,
expiration dates of stick-tables entries were not synchronized between peers.
This patch adds two new stick-table messages to provide such a synchronization feature.
As these new messages are not supported by older haproxy peers protocol versions,
this patch increments peers protol version, from 2.0 to 2.1, to help in detecting/supporting
such older peers protocol implementations so that new versions might still be able
to transparently communicate with a newer one.
[wt: technically speaking it would be nice to have this backported into 1.6
as some people who reload often are affected by this design limitation, but
it's not a totally transparent change that may make certain users feel
reluctant to upgrade older versions. Let's let it cook in 1.7 first and
decide later]
The fe_req_rate is similar to fe_sess_rate, but fetches the number
of HTTP requests per second instead of connections/sessions per second.
Signed-off-by: Nenad Merdanovic <nmerdan@anine.io>
dns_init_resolvers() tries to emit the current resolver's name in the
error message in case of out-of-memory condition. But it must not do
it when initializing the trash before even having such a resolver
otherwise the user is certain to get a dirty crash instead of the
error message. No backport is needed.
An apparent copy-paste error resulted in backend's avg connection time
to report the average queue time instead in the HTML dump. Backport to
1.6 is desired.
When the compression is enable on HTTP responses, the chunked data are copied in
a temporary buffer during the HTTP body parsing and then compressed when
everything is forwarded to the client. But the amout of data that can be copied
was not correctly calculated. In many cases, it worked, else on the edge when
the channel buffer was almost full.
[wt: bug introduced by b77c5c26 in 1.7-dev, no backport needed]
Enable IP_BIND_ADDRESS_NO_PORT on backend connections when the source
address is specified without port or port ranges. This is supported
since Linux 4.2/libc 2.23.
If the kernel supports it but the libc doesn't, we can define it at
build time:
make [...] DEFINE=-DIP_BIND_ADDRESS_NO_PORT=24
For more informations about this feature, see Linux commit 90c337da
With Linux officially introducing SO_REUSEPORT support in 3.9 and
its mainstream adoption we have seen more people running into strange
SO_REUSEPORT related issues (a process management issue turning into
hard to diagnose problems because the kernel load-balances between the
new and an obsolete haproxy instance).
Also some people simply want the guarantee that the bind fails when
the old process is still bound.
This change makes SO_REUSEPORT configurable, introducing the command
line argument "-dR" and the noreuseport configuration directive.
A backport to 1.6 should be considered.
pcre_version() returns the running PCRE release, not the release
haproxy was built with.
This simple string fix should be backported to supported releases,
as the output may be confusing.
To avoid issues when porting code to some architecture, we need to know
the endianess the structures are currently used.
This patch simply had a short notice before those structures to report
endianess and ease contributor's job.
The analyse of CNAME resolution and request's domain name was performed
twice:
- when validating the response buffer
- when loading the right IP address from the response
Now DNS response are properly loaded into a DNS response structure, we
do the domain name validation when loading/validating the response in
the DNS strcucture and later processing of this task is now useless.
backport: no
DNS servers don't return A or AAAA record if the query points to a CNAME
not resolving to the right type.
We know it because the last record of the response is a CNAME. We can
trigger a new query, switching to a new query type, handled by the layer
above.
New DNS response parser function which turn the DNS response from a
network buffer into a DNS structure, much easier for later analysis
by upper layer.
Memory is pre-allocated at start-up in a chunk dedicated to DNS
response store.
New error code to report a wrong number of queries in a DNS response.
struct dns_query_item: describes a DNS query record
struct dns_answer_item: describes a DNS answer record
struct dns_response_packet: describes a DNS response packet
DNS_MIN_RECORD_SIZE: minimal size of a DNS record
DNS_MAX_QUERY_RECORDS: maximum number of query records we allow.
For now, we send one DNS query per request.
DNS_MAX_ANSWER_RECORDS: maximum number of records we may found in a
response
WIP dns: new MAX values
Current implementation of HAProxy's DNS resolution expect only 512 bytes
of data in the response.
Update DNS_MAX_UDP_MESSAGE to match this.
Backport: can be backported to 1.6
Enrichment of the 'set server <b>/<s> addr' cli directive to allow changing
now a server's port.
The new syntax looks like:
set server <b>/<s> addr [port <port>]
This function can replace update_server_addr() where the need to change the
server's port as well as the IP address is required.
It performs some validation before performing each type of change.
Introduction of 3 new server flags to remember if some parameters were set
during configuration parsing.
* SRV_F_CHECKADDR: this server has a check addr configured
* SRV_F_CHECKPORT: this server has a check port configured
* SRV_F_AGENTADDR: this server has a agent addr configured
HAProxy used to deduce port used for health checks when parsing configuration
at startup time.
Because of this way of working, it makes it complicated to change the port at
run time.
The current patch changes this behavior and makes HAProxy to choose the
port used for health checking when preparing the check task itself.
A new type of error is introduced and reported when no port can be found.
There won't be any impact on performance, since the process to find out the
port value is made of a few 'if' statements.
This patch also introduces a new check state CHK_ST_PORT_MISS: this flag is
used to report an error in the case when HAProxy needs to establish a TCP
connection to a server, to perform a health check but no TCP ports can be
found for it.
And last, it also introduces a new stream termination condition:
SF_ERR_CHK_PORT. Purpose of this flag is to report an error in the event when
HAProxy has to run a health check but no port can be found to perform it.
SOL_IPV6 is not defined on OSX, breaking the compile. Also libcrypt is
not available for installation neither in Macports nor as a Brew recipe,
so we're disabling implicit dependancy.
Signed-off-by: Dinko Korunic <dinko.korunic@gmail.com>
Introduction of a new CLI command "set server <srv> check-port <port>' to
allow admins to change a server's health check port at run time.
This changes the equivalent of the configuration server parameter
called 'port'.
Today I was working on an auto-update script for some ACLs, and found
that I couldn't load ACL entries with a semi-colon in them no matter
how I tried to escape it.
As such, I wrote this patch (this one is for 1.7dev, but it applies to
1.5 the same with just line numbers changed), which seems to allow me
to execute a command such as "add acl /etc/foo.lst foo\;bar" over the
socket. It's worth noting that stats_sock_parse_request() already uses
the backslash to escape spaces in words so it makes sense to use it as
well to escape the semi-colon.
A typo resulting from a copy-paste in the original req.ssl_ver code will
make certain SSLv2 hello messages not properly detected. The bug has been
present since the code was added in 1.3.16. In 1.3 and 1.4, this code was
in proto_tcp.c. In 1.5-dev0, it moved to acl.c, then later to payload.c.
This bug was tagged "minor" because SSLv2 is outdated and this encoding
was rarely (if at all) used, the shorter form starting with 0x80 being
more common.
This fix needs to be backported to all currently maintained branches.
In dns_send_query(), ret was set to 0 but always reassigned before the
usage so this initialisation was useless.
The send_error variable was created, assigned to 0 but never used. So
this variable is just useless by itself. Removing it.
In dump_servers_state(), srv_time_since_last_change, bk_f_forced_id, srv_f_forced_id variables
were firstly set to zero and immediately reassigned to another value while never been accessed in between.
Sounds like a useless initiazation. So let's make only the useful allocation.
Bartosz Koninski reported that recent commit 568743a ("BUG/MEDIUM: stream-int:
completely detach connection on connect error") introduced a nasty side effect
during the connection retry, causing a reconnect attempt to be performed on a
random address, possibly another server from another backend as shown in his
reproducer.
The real reason is in fact that by calling si_release_endpoint() after a
failed connect attempt and not clearing the SN_ADDR_SET flag on the
stream, we indicate that we continue to trust the connection's current
address. So upon next connect attempt, a connection is picked from the
pool and the last target address is reused. It is not very easy to
reproduce it 100% reliably out of production traffic, but it's easier to
see when haproxy is started with -dM to force the pools to be filled with
junk, and where subsequent connections are not even attempted due to their
family being incorrect.
The correct fix consists in clearing the SN_ADDR_SET flag after calling
si_release_endpoint() during a retry. But it outlines a deeper issue which
is in fact that the target address is *stored* in the connection and its
validity is stored in the stream. Until we have a better solution to store
target addresses, it would be better to rely on the connection flags
(CO_FL_ADDR_TO_SET) for this purpose. But it also outlines the fact that
the same issue still exists in Lua sockets and in idle sockets, which
fortunately are not affected by this issue.
Thanks to Bartosz for providing all the elements needed to understand the
problem.
This fix needs to be backported to 1.6 and 1.5.
Trie now uses a dataset structure just like Pattern, so this has been
defined in includes/types/global.h for both Pattern and Trie where it
was just Pattern.
In src/51d.c all functions used by the Trie implementation which need a
dataset as an argument now use the global dataset. The
fiftyoneDegreesDestroy method has now been replaced with
fiftyoneDegreesDataSetFree which is common to Pattern and Trie. In
addition, two extra dataset init status' have been added to the switch
statement in init_51degrees.
A few log format fields were declared but never used, so let's drop
them, the whole list is confusing enough already :
LOG_FMT_VARIABLE, LOG_FMT_T, LOG_FMT_CONN, LOG_FMT_QUEUES.
Tq is the time between the instant the connection is accepted and a
complete valid request is received. This time includes the handshake
(SSL / Proxy-Protocol), the idle when the browser does preconnect and
the request reception.
This patch decomposes %Tq in 3 measurements names %Th, %Ti, and %TR
which returns respectively the handshake time, the idle time and the
duration of valid request reception. It also adds %Ta which reports
the request's active time, which is the total time without %Th nor %Ti.
It replaces %Tt as the total time, reporting accurate measurements for
HTTP persistent connections.
%Th is avalaible for TCP and HTTP sessions, %Ti, %TR and %Ta are only
avalaible for HTTP connections.
In addition to this, we have new timestamps %tr, %trg and %trl, which
log the date of start of receipt of the request, respectively in the
default format, in GMT time and in local time (by analogy with %t, %T
and %Tl). All of them are obviously only available for HTTP. These values
are more relevant as they more accurately represent the request date
without being skewed by a browser's preconnect nor a keep-alive idle
time.
The HTTP log format and the CLF log format have been modified to
use %tr, %TR, and %Ta respectively instead of %t, %Tq and %Tt. This
way the default log formats now produce the expected output for users
who don't want to manually fiddle with the log-format directive.
Example with the following log-format :
log-format "%ci:%cp [%tr] %ft %b/%s h=%Th/i=%Ti/R=%TR/w=%Tw/c=%Tc/r=%Tr/a=%Ta/t=%Tt %ST %B %CC %CS %tsc %ac/%fc/%bc/%sc/%rc %sq/%bq %hr %hs %{+Q}r"
The request was sent by hand using "openssl s_client -connect" :
Aug 23 14:43:20 haproxy[25446]: 127.0.0.1:45636 [23/Aug/2016:14:43:20.221] test~ test/test h=6/i=2375/R=261/w=0/c=1/r=0/a=262/t=2643 200 145 - - ---- 1/1/0/0/0 0/0 "GET / HTTP/1.1"
=> 6 ms of SSL handshake, 2375 waiting before sending the first char (in
fact the time to type the first line), 261 ms before the end of the request,
no time spent in queue, 1 ms spend connecting to the server, immediate
response, total active time for this request = 262ms. Total time from accept
to close : 2643 ms.
The timing now decomposes like this :
first request 2nd request
|<-------------------------------->|<-------------- ...
t tr t tr ...
---|----|----|----|----|----|----|----|----|--
: Th Ti TR Tw Tc Tr Td : Ti ...
:<---- Tq ---->: :
:<-------------- Tt -------------->:
:<--------- Ta --------->:
Released version 1.7-dev4 with the following main changes :
- MINOR: add list_append_word function
- MEDIUM: init: use list_append_word in haproxy.c
- MEDIUM: init: allow directory as argument of -f
- CLEANUP: config: detect double registration of a config section
- MINOR: log: add the %Td log-format specifier
- MEDIUM: filters: Move HTTP headers filtering in its own callback
- MINOR: filters: Simplify calls to analyzers using 2 new macros
- MEDIUM: filters: Add pre and post analyzer callbacks
- DOC: filters: Update the filters documentation accordingly to recent changes
- BUG/MEDIUM: init: don't use environment locale
- SCRIPTS: teach git-show-backports how to report upstream commits
- SCRIPTS: make git-show-backports capable of limiting its history
- BUG/MAJOR: fix listening IP address storage for frontends
- BUG/MINOR: fix listening IP address storage for frontends (cont)
- DOC: Fix typo so fetch is properly parsed by Cyril's converter
- BUG/MAJOR: http: fix breakage of "reqdeny" causing random crashes
- BUG/MEDIUM: stick-tables: fix breakage in table converters
- MINOR: stick-table: change all stick-table converters' inputs to SMP_T_ANY
- BUG/MEDIUM: dns: unbreak DNS resolver after header fix
- BUILD: fix build on Solaris 11
- BUG/MEDIUM: config: fix multiple declaration of section parsers
- BUG/MEDIUM: stats: show servers state may show an servers from another backend
- BUG/MEDIUM: fix risk of segfault with "show tls-keys"
- MEDIUM: dumpstats: 'show tls-keys' is now able to show secrets
- DOC: update doc about tls-tickets-keys dump
- MEDIUM: tcp: add 'set-src' to 'tcp-request connection'
- MINOR: set the CO_FL_ADDR_FROM_SET flags with 'set-src'
- MEDIUM: tcp/http: add 'set-src-port' action
- MEDIUM: tcp/http: new set-dst/set-dst-port actions
- BUG/MEDIUM: sticktables: segfault in some configuration error cases
- BUILD/MEDIUM: rebuild everything when an include file is changed
- BUILD/MEDIUM: force a full rebuild if some build options change
- BUG/MEDIUM: lua: converters doesn't work
- BUG/MINOR: http: add-header: header name copied twice
- BUG/MEDIUM: http: add-header: buffer overwritten
- BUG/MINOR: ssl: fix potential memory leak in ssl_sock_load_dh_params()
- MINOR: stream: export the function 'smp_create_src_stkctr'
- BUG/MEDIUM: dumpstats: undefined behavior in stats_tlskeys_list()
- MEDIUM: dumpstats: make stats_tlskeys_list() yield-aware during tls-keys dump
- BUG/MINOR: http: url32+src should use the big endian version of url32
- BUG/MINOR: http: url32+src should check cli_conn before using it
- DOC: http: add documentation for url32 and url32+src
- BUG/MINOR: fix http-response set-log-level parsing error
- MINOR: systemd: Use variable for config and pidfile paths
- MINOR: systemd: Perform sanity check on config before reload
- MEDIUM: ssl: support SNI filters with multicerts
- MINOR: ssl: crt-list parsing factor
- BUILD: ssl: fix typo causing a build failure in the multicert patch
- MINOR: listener: add the "accept-netscaler-cip" option to the "bind" keyword
- MINOR: tcp: add "tcp-request connection expect-netscaler-cip layer4"
- BUG/MINOR: init: always ensure that global.rlimit_nofile matches actual limits
- BUG/MINOR: init: ensure that FD limit is raised to the max allowed
- BUG/MEDIUM: external-checks: close all FDs right after the fork()
- BUG/MAJOR: external-checks: use asynchronous signal delivery
- BUG/MINOR: external-checks: do not unblock undesired signals
- CLEANUP: external-check: don't block/unblock SIGCHLD when manipulating the list
- BUG/MEDIUM: filters: Fix data filtering when data are modified
- BUG/MINOR: filters: Fix HTTP parsing when a filter loops on data forwarding
- BUG/MINOR: srv-state: fix incorrect output of state file
- BUG/MINOR: ssl: close ssl key file on error
- BUG/MINOR: http: fix misleading error message for response captures
- BUG/BUILD: don't automatically run "make" on "make install"
- DOC: add missing doc for http-request deny [deny_status <status>]
- CLEANUP: dumpstats: u64 field is an unsigned type.
- BUG/MEDIUM: http: unbreak uri/header/url_param hashing
- BUG/MINOR: Rework slightly commit 9962f8fc to clean code and avoid mistakes
- MINOR: new function my_realloc2 = realloc + free upon failure
- CLEANUP: fixed some usages of realloc leading to memory leak
- Revert "BUG/MINOR: ssl: fix potential memory leak in ssl_sock_load_dh_params()"
- CLEANUP: connection: using internal struct to hold source and dest port.
- DOC: spelling fixes
- BUG/MINOR: ssl: fix potential memory leak in ssl_sock_load_dh_params()
- BUG/MEDIUM: dns: fix alignment issues in the DNS response parser
- BUG/MINOR: Fix endiness issue in DNS header creation code
- BUG/MEDIUM: lua: the function txn_done() from sample fetches can crash
- BUG/MEDIUM: lua: the function txn_done() from action wrapper can crash
- MEDIUM: http: implement http-response track-sc* directive
- BUG/MINOR: peers: Fix peers data decoding issue
- BUG/MINOR: peers: don't count track-sc multiple times on errors
- MINOR: standard: add function "escape_string"
- BUG/MEDIUM: log: use function "escape_string" instead of "escape_chunk"
- MINOR: tcp: Return TCP statistics like RTT and RTT variance
- DOC: lua: remove old functions
- BUG/MEDIUM: lua: somme HTTP manipulation functions are called without valid requests
- DOC: fix json converter example and error message
- BUG/MEDIUM: stream-int: completely detach connection on connect error
- DOC: minor typo fixes to improve HTML parsing by haproxy-dconv
- BUILD: make proto_tcp.c compatible with musl library
- BUG/MAJOR: compression: initialize avail_in/next_in even during flush
- BUG/MEDIUM: samples: make smp_dup() always duplicate the sample
- MINOR: sample: implement smp_is_safe() and smp_make_safe()
- MINOR: sample: provide smp_is_rw() and smp_make_rw()
- BUG/MAJOR: server: the "sni" directive could randomly cause trouble
- BUG/MEDIUM: stick-tables: do not fail on string keys with no allocated size
- BUG/MEDIUM: stick-table: properly convert binary samples to keys
- MINOR: sample: use smp_make_rw() in upper/lower converters
- MINOR: tcp: add dst_is_local and src_is_local
- BUG/MINOR: peers: some updates are pushed twice after a resync.
- BUILD: protocol: fix some build errors on OpenBSD
- BUILD: log: iovec requires to include sys/uio.h on OpenBSD
- BUILD: tcp: do not include netinet/ip.h for IP_TTL
- BUILD: connection: fix build breakage on openbsd due to missing in_systm.h
- BUILD: checks: remove the last strcat and eliminate a warning on OpenBSD
- BUILD: tcp: define SOL_TCP when only IPPROTO_TCP exists
- BUILD: compression: remove a warning when no compression lib is used
- BUILD: poll: remove unused hap_fd_isset() which causes a warning with clang
- MINOR: tcp: add further tcp info fetchers
- BUG/MINOR: peers: empty chunks after a resync.
- BUG/MAJOR: stick-counters: possible crash when using sc_trackers with wrong table
- MINOR: standard.c: ipcmp() function to compare 2 IP addresses stored in 2 struct sockaddr_storage
- MINOR: standard.c: ipcpy() function to copy an IP address from a struct sockaddr_storage into an other one
- MAJOR: listen section: don't use first bind port anymore when no server ports are provided
Up to HAProxy 1.7-dev3, HAProxy used to use the first bind port from it's
local 'listen' section when no port is configured on the server.
IE, in the configuration below, the server port would be 25:
listen smtp
bind :25
server s1 1.0.0.1 check
This way of working is now obsolete and can be removed, furthermore it is not
documented!
This will make the possibility to change the server's port much easier.
The function ipcpy() simply duplicates the IP address found in one
struct sockaddr_storage into an other struct sockaddr_storage.
It also update the family on the destination structure.
Memory of destination structure must be allocated and cleared by the
caller.
Bryan Talbot reported a very interesting bug. The sc_trackers() sample
fetch seems to have escaped the sanitization that was performed during 1.5
to ensure all dereferences of stkctr_entry() were safe. Here if a tacker
is set on a backend and is then checked against a different backend where
the entry doesn't exist, stkctr_entry() returns NULL and this is dereferenced
to retrieve the ref count. Thanks to Bryan for his detailed bug report featuring
a working config and reproducer.
This fix must be backported to 1.6 and 1.5.
After pushing the last update related to a resync process, the teacher resets
the re-connection's origin to the saved one (pointer position when he receive
the resync request). But the last acknowledgement overwrites this pointer to
an inconsistent value. In peersv2, it results with empty table chunks
regularly pushed.
The fix consist to move the confirm code to assure that the confirm message is
always sent after the last acknowledgement related to the resync. And to reset
the re-connection's origin to the saved one when a confirm message is received.
This bug affects versions 1.6 and superior.
For older versions (peersv1), this inconsistent state should not generate side
effects because chunks are not used and a next acknowlegement message resets
the pointer in a valid state.
Adding on to Thierry's work (http://git.haproxy.org/?p=haproxy.git;h=6310bef5)
I have added a few more fetchers for counters based on the tcp_info struct
maintained by the kernel :
fc_unacked, fc_sacked, fc_retrans, fc_fackets, fc_lost,
fc_reordering
Two fields were not added because they're version-dependant :
fc_rcv_rtt, fc_total_retrans
The fields name depend on the operating system. FreeBSD and NetBSD prefix
all the field names with "__" so we have to rely on a few #ifdef for
portability.
Clang reports that this function is not used :
src/ev_poll.c:34:28: warning: unused function 'hap_fd_isset' [-Wunused-function]
static inline unsigned int hap_fd_isset(int fd, unsigned int *evts)
It's been true since the rework of the pollers in 1.5 and it's unlikely we'll
ever need it anymore, so better remove it now to provide clean builds.
This fix can be backported to 1.6 and 1.5 now.
This warning appears when building without any compression library :
src/compression.c:143:19: warning: unused function 'init_comp_ctx' [-Wunused-function]
static inline int init_comp_ctx(struct comp_ctx **comp_ctx)
^
src/compression.c:176:19: warning: unused function 'deinit_comp_ctx' [-Wunused-function]
static inline int deinit_comp_ctx(struct comp_ctx **comp_ctx)
No backport is needed.
FreeBSD prefers to use IPPROTO_TCP over SOL_TCP, just like it does
with their *_IP counterparts. It's worth noting that there are a few
inconsistencies between SOL_TCP and IPPROTO_TCP in the code, eg on
TCP_QUICKACK. The two values are the same but it's worth applying
what implementations recommend.
No backport is needed, this was uncovered by the recent tcp_info stuff.
