[MINOR] Add rdp_cookie pattern fetch function

This pattern fetch function extracts the value of the rdp cookie <name> as
a string and uses this value to match. This enables implementation of
persistence based on the mstshash cookie. This is typically done if there
is no msts cookie present.

This differs from "balance rdp-cookie" in that any balancing algorithm may
be used and thus the distribution of clients to backend servers is not
linked to a hash of the RDP cookie. It is envisaged that using a balancing
algorithm such as "balance roundrobin" or "balance leastconnect" will lead
to a more even distribution of clients to backend servers than the hash
used by "balance rdp-cookie".

Example :
	listen tse-farm
	    bind 0.0.0.0:3389
	    # wait up to 5s for an RDP cookie in the request
	    tcp-request inspect-delay 5s
	    tcp-request content accept if RDP_COOKIE
	    # apply RDP cookie persistence
	    persist rdp-cookie
	    # Persist based on the mstshash cookie
	    # This is only useful makes sense if
	    # balance rdp-cookie is not used
	    stick-table type string size 204800
	    stick on rdp_cookie(mstshash)
	    server srv1 1.1.1.1:3389
	    server srv1 1.1.1.2:3389

diff --git a/doc/configuration.txt b/doc/configuration.txt
index b28e85198151271b36b84af10b43b1012c8e0abe..89d6dd7097b6c82d8e0567acb354c92dfba4e60c 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1352,6 +1352,8 @@ balance url_param <param> [check_post [<max_wait>]]
                   changing a server's weight on the fly will have no effect,
                   but this can be changed using "hash-type".
 
+                 See also the rdp_cookie pattern fetch function.
+
     <arguments> is an optional list of arguments which may be needed by some
                 algorithms. Right now, only "url_param" and "uri" support an
                 optional argument.
@@ -4127,7 +4129,8 @@ persist rdp-cookie(name)
             server srv1 1.1.1.1:3389
             server srv2 1.1.1.2:3389
 
-  See also : "balance rdp-cookie", "tcp-request" and the "req_rdp_cookie" ACL.
+  See also : "balance rdp-cookie", "tcp-request", the "req_rdp_cookie" ACL and
+  the rdp_cookie pattern fetch function.
 
 
 rate-limit sessions <rate>
@@ -7928,6 +7931,40 @@ The list of currently supported pattern fetch functions is the following :
               http://example.com/foo?JESSIONID=some_id with
               url_param(JSESSIONID)), for cases where cookies cannot be used.
 
+  rdp_cookie(name)
+              This extracts the value of the rdp cookie <name> as a string
+              and uses this value to match. This enables implementation of
+              persistence based on the mstshash cookie. This is typically
+              done if there is no msts cookie present.
+
+              This differs from "balance rdp-cookie" in that any balancing
+              algorithm may be used and thus the distribution of clients
+              to backend servers is not linked to a hash of the RDP
+              cookie. It is envisaged that using a balancing algorithm
+              such as "balance roundrobin" or "balance leastconnect" will
+              lead to a more even distribution of clients to backend
+              servers than the hash used by "balance rdp-cookie".
+
+              Example :
+               listen tse-farm
+                   bind 0.0.0.0:3389
+                   # wait up to 5s for an RDP cookie in the request
+                   tcp-request inspect-delay 5s
+                   tcp-request content accept if RDP_COOKIE
+                   # apply RDP cookie persistence
+                   persist rdp-cookie
+                   # Persist based on the mstshash cookie
+                   # This is only useful makes sense if
+                   # balance rdp-cookie is not used
+                   stick-table type string size 204800
+                   stick on rdp_cookie(mstshash)
+                   server srv1 1.1.1.1:3389
+                   server srv1 1.1.1.2:3389
+
+              See also : "balance rdp-cookie", "persist rdp-cookie",
+              "tcp-request" and the "req_rdp_cookie" ACL.
+
+
 The currently available list of transformations include :
 
   lower        Convert a string pattern to lower case. This can only be placed

diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index e6d6c58a0a699004151518753437d0e9aa1d4662..f03d3f338d804239df4678eea5f73fc44a10e055 100644 (file)
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -1578,6 +1578,32 @@ pattern_fetch_payload(struct proxy *px, struct session *l4, void *l7, int dir,
        return 1;
 }
 
+static int
+pattern_fetch_rdp_cookie(struct proxy *px, struct session *l4, void *l7, int dir,
+                         const struct pattern_arg *arg_p, int arg_i, union pattern_data *data)
+{
+       int ret;
+       struct acl_expr  expr;
+       struct acl_test  test;
+
+       if (!l4)
+               return 0;
+
+       memset(&expr, 0, sizeof(expr));
+       memset(&test, 0, sizeof(test));
+
+       expr.arg.str = arg_p[0].data.str.str;
+       expr.arg_len = arg_p[0].data.str.len;
+
+       ret = acl_fetch_rdp_cookie(px, l4, NULL, ACL_DIR_REQ, &expr, &test);
+       if (ret == 0 || (test.flags & ACL_TEST_F_MAY_CHANGE) || test.len == 0)
+               return 0;
+
+       /* init chunk as read only */
+       chunk_initlen(&data->str, test.ptr, 0, test.len);
+       return 1;
+}
+
 static struct cfg_kw_list cfg_kws = {{ },{
        { CFG_LISTEN, "tcp-request", tcp_parse_tcp_req },
        { CFG_LISTEN, "tcp-response", tcp_parse_tcp_rep },
@@ -1602,6 +1628,7 @@ static struct pattern_fetch_kw_list pattern_fetch_keywords = {{ },{
        { "dst_port",    pattern_fetch_dport,     NULL,                         PATTERN_TYPE_INTEGER,   PATTERN_FETCH_REQ },
        { "payload",     pattern_fetch_payload,   pattern_arg_fetch_payload,    PATTERN_TYPE_CONSTDATA, PATTERN_FETCH_REQ|PATTERN_FETCH_RTR },
        { "payload_lv",  pattern_fetch_payloadlv, pattern_arg_fetch_payloadlv,  PATTERN_TYPE_CONSTDATA, PATTERN_FETCH_REQ|PATTERN_FETCH_RTR },
+       { "rdp_cookie",  pattern_fetch_rdp_cookie, pattern_arg_str,             PATTERN_TYPE_CONSTSTRING, PATTERN_FETCH_REQ },
        { NULL, NULL, NULL, 0, 0 },
 }};