route return value confusion

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RTP rePacketization

Juha Heinanen

10 Dec 2011 10 Dec '11

4:16 p.m.

i have defined two routes: route [TEST_ROUTE_MINUS_ONE] { return (-1); } route [TEST_ROUTE_PLUS_ONE] { return (1); } and then test them with these statements: if (route(TEST_ROUTE_MINUS_ONE) == -1) { xlog("L_INFO", "TEST_ROUTE returned -1\n"); } if (!route(TEST_ROUTE_MINUS_ONE)) { xlog("L_INFO", "TEST_ROUTE returned failure\n"); } if (route(TEST_ROUTE_PLUS_ONE) == 1) { xlog("L_INFO", "TEST_ROUTE returned 1\n"); } if (route(TEST_ROUTE_PLUS_ONE)) { xlog("L_INFO", "TEST_ROUTE returned success\n"); } can someone explain, why i get only three lines to syslog? Dec 10 16:14:56 sip /usr/sbin/sip-proxy[16099]: INFO: TEST_ROUTE_MINUS_ONE returned failure Dec 10 16:14:56 sip /usr/sbin/sip-proxy[16099]: INFO: TEST_ROUTE_PLUS_ONE returned 1 Dec 10 16:14:56 sip /usr/sbin/sip-proxy[16099]: INFO: TEST_ROUTE_PLUS_ONE returned success -- juha

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Daniel-Constantin Mierla

12 Dec 12 Dec

11:36 a.m.

Hello, cannot test it for now personally, but what you get if you do: route(TEST_ROUTE_MINUS_ONE); $var(r) = $rc; xlog("returned code by route minus one is: $var(r)\n"); Maybe this will give some leads I can follow in the code... Cheers, Daniel On 12/10/11 3:16 PM, Juha Heinanen wrote:

...

-- Daniel-Constantin Mierla -- http://www.asipto.com http://linkedin.com/in/miconda -- http://twitter.com/miconda

Juha Heinanen

11:45 a.m.

Daniel-Constantin Mierla writes:

...

cannot test it for now personally, but what you get if you do: route(TEST_ROUTE_MINUS_ONE); $var(r) = $rc; xlog("returned code by route minus one is: $var(r)\n"); Maybe this will give some leads I can follow in the code...

daniel, i correctly get: Dec 12 11:42:37 sip /usr/sbin/sip-proxy[1308]: ERROR: returned code by route minus one is: -1 so it is only the test if (route(TEST_ROUTE_MINUS_ONE) == -1) ... that fails. -- juha

Daniel-Constantin Mierla

12:29 p.m.

Hello, On 12/12/11 10:45 AM, Juha Heinanen wrote:

...

Daniel-Constantin Mierla writes:

daniel, i correctly get: Dec 12 11:42:37 sip /usr/sbin/sip-proxy[1308]: ERROR: returned code by route minus one is: -1 so it is only the test if (route(TEST_ROUTE_MINUS_ONE) == -1) ... that fails.

ok, so looks like IF with a mod function returning negative needs investigation. I will look over it soon. Cheers, Daniel -- Daniel-Constantin Mierla -- http://www.asipto.com http://linkedin.com/in/miconda -- http://twitter.com/miconda

Daniel-Constantin Mierla

13 Dec 13 Dec

1:56 p.m.

Hello, I checked the code and this behaviour is practically due to special meaning of return codes from functions exported to config file, ie,: - <0 is false - >0 is true route(x) call is returning the code from route block itself, but then the interpreter converts the codes < 0 to 0 (so the condition is false in C) and the codes > 0 to 1 (so the condition is C is true). Thus, no matter what code you return from a subroute, you have to compare against 0 (for negative return code) or 1 (for positive return code). Solutions/alternatives: 1) $var(r) = route(x); .. and then compare $var(r) 2) route(x); $var(r) = $rc; .. and then compare $var(r) 3) doing it in the if: if(($var(r) = route(x)) && ($var(r) == -1)) { ... } The assignment which is done first in the IF expression will return true if the assignment operation is successful. Cheers, Daniel just replace -1 with the return code you want to test against On 12/12/11 11:29 AM, Daniel-Constantin Mierla wrote:

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Hello, On 12/12/11 10:45 AM, Juha Heinanen wrote:

Daniel-Constantin Mierla writes:

daniel, i correctly get: Dec 12 11:42:37 sip /usr/sbin/sip-proxy[1308]: ERROR: returned code by route minus one is: -1 so it is only the test if (route(TEST_ROUTE_MINUS_ONE) == -1) ... that fails.

ok, so looks like IF with a mod function returning negative needs investigation. I will look over it soon. Cheers, Daniel

-- Daniel-Constantin Mierla -- http://www.asipto.com http://linkedin.com/in/miconda -- http://twitter.com/miconda

Juha Heinanen

2:03 p.m.

Daniel-Constantin Mierla writes:

...

Thus, no matter what code you return from a subroute, you have to compare against 0 (for negative return code) or 1 (for positive return code). Solutions/alternatives:

is it not an alternative to fix to change the current implementation so that the real return code of route block could be tested? -- juha

Daniel-Constantin Mierla

2:19 p.m.

On 12/13/11 1:03 PM, Juha Heinanen wrote:

...

Daniel-Constantin Mierla writes:

Thus, no matter what code you return from a subroute, you have to compare against 0 (for negative return code) or 1 (for positive return code). Solutions/alternatives:

is it not an alternative to fix to change the current implementation so that the real return code of route block could be tested?

coding wise might not be a lot, thus I haven't analyzed all the cases where functions are evaluated by return code, but it will impact and break config file as it used to be so far, for example: route[x] { return -1; } if(route(x)) will be true, since if(-1) is true in C All conditions with functions have to be changed in: if( f()<0 ) for false cases if( f(x) > 0) for true cases At this moment I cannot say for sure if there can be done some workaround to get return code and keep old behavior, at first sight seems unlikely. Cheers, Daniel -- Daniel-Constantin Mierla -- http://www.asipto.com http://linkedin.com/in/miconda -- http://twitter.com/miconda

Juha Heinanen

2:25 p.m.

Daniel-Constantin Mierla writes:

...

i meant get rid of C interpretation when if evaluates the condition, i.e., do not covert condition to anything, but just test if condition is < 0 for false and > 0 for true. -- juha

Daniel-Constantin Mierla

2:36 p.m.

On 12/13/11 1:25 PM, Juha Heinanen wrote:

...

Daniel-Constantin Mierla writes:

i meant get rid of C interpretation when if evaluates the condition, i.e., do not covert condition to anything, but just test if condition is < 0 for false and> 0 for true.

This is what happens actually: if(route(x) == 1) is seen by interpreter as: if(left_expression == 1) then left_expression is evaluated as you say above: - < 0 is false => this is 0 is C - > 0 is true => this is 1 in C Since left_expression can be complex (include sub expressions), there has to be propagation to false/true. For example you can have in the left expression (2<1) or variables with such values. Anyhow, if you have some ideas, you can play with functions in lvalue.c, rvalue.c and action.c Cheers, Daniel -- Daniel-Constantin Mierla -- http://www.asipto.com http://linkedin.com/in/miconda -- http://twitter.com/miconda

Morten Isaksen

12 Dec 12 Dec

12:15 p.m.

I had a similar problem with avp_db_query if (avp_db_query(...) == -2) { xlog("..."); } did not work, but $var(r) = avp_db_query(....); if ($var(r) == -2) { xlog("..."); } did work. /Morten On Sat, Dec 10, 2011 at 3:16 PM, Juha Heinanen <jh(a)tutpro.com> wrote:

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-- Morten Isaksen

Daniel-Constantin Mierla

13 Dec 13 Dec

1:59 p.m.

Hello, On 12/12/11 11:15 AM, Morten Isaksen wrote:

...

I had a similar problem with avp_db_query if (avp_db_query(...) == -2) { xlog("..."); } did not work, but $var(r) = avp_db_query(....); if ($var(r) == -2) { xlog("..."); } did work.

indeed, this is a solution. As stated in the previous email, inside an IF expression, the return code from functions exported to config are converted to 0 if return code is < 0 and to 1 if the return code is >0 to match in C the special meaning of return codes in the config file. Cheers, Daniel

...

/Morten On Sat, Dec 10, 2011 at 3:16 PM, Juha Heinanen<jh(a)tutpro.com> wrote:

-- Daniel-Constantin Mierla -- http://www.asipto.com http://linkedin.com/in/miconda -- http://twitter.com/miconda

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Daniel-Constantin Mierla
Juha Heinanen
Morten Isaksen