diff options
| -rw-r--r-- | doc/doc-txt/ChangeLog | 7 | ||||
| -rw-r--r-- | src/src/dns.c | 161 |
2 files changed, 133 insertions, 35 deletions
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index 1338d3d63..5ac7397a8 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.228 2005/09/13 11:27:45 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.229 2005/09/13 15:40:07 ph10 Exp $ Change log file for Exim from version 4.21 ------------------------------------------- @@ -183,6 +183,11 @@ PH/45 Added $smtp_command for the full command (cf $smtp_command_argument). PH/46 Added extra information about PostgreSQL errors to the error string. +PH/47 Added an interface to a fake DNS resolver for use by the new test suite, + avoiding the need to install special zones in a real server. This is + backwards compatible; if it can't find the fake resolver, it drops back. + Thus, both old and new test suites can be run. + Exim version 4.52 ----------------- diff --git a/src/src/dns.c b/src/src/dns.c index 882e0f316..83daf50f3 100644 --- a/src/src/dns.c +++ b/src/src/dns.c @@ -1,4 +1,4 @@ -/* $Cambridge: exim/src/src/dns.c,v 1.9 2005/06/29 10:56:35 ph10 Exp $ */ +/* $Cambridge: exim/src/src/dns.c,v 1.10 2005/09/13 15:40:07 ph10 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * @@ -23,6 +23,120 @@ static void dns_complete_a6(dns_address ***, dns_answer *, dns_record *, #endif +/************************************************* +* Fake DNS resolver * +*************************************************/ + +/* This function is called instead of res_search() when Exim is running in its +test harness. It recognizes some special domain names, and uses them to force +failure and retry responses (optionally with a delay). It also recognises the +zones test.ex and 10.in-addr.arpa, and for those it calls an external utility +that mock-up a nameserver, if it can find the utility. Otherwise, it passes its +arguments on to res_search(). + +Background: the original test suite required a real nameserver to carry the +test.ex and 10.in-addr.arpa zones, whereas the new test suit has the fake +server for portability. This code supports both. + +Arguments: + name the domain name + type the DNS record type + answerptr where to put the answer + size size of the answer area + +Returns: length of returned data, or -1 on error (h_errno set) +*/ + +static int +fakens_search(uschar *name, int type, uschar *answerptr, int size) +{ +int len = Ustrlen(name); +uschar *endname = name + len; + +if (len >= 14 && Ustrcmp(endname - 14, "test.again.dns") == 0) + { + int delay = Uatoi(name); /* digits at the start of the name */ + DEBUG(D_dns) debug_printf("Return from DNS lookup of %s (%s) faked for testing\n", + name, dns_text_type(type)); + if (delay > 0) + { + DEBUG(D_dns) debug_printf("delaying %d seconds\n", delay); + sleep(delay); + } + h_errno = TRY_AGAIN; + return -1; + } + +if (len >= 13 && Ustrcmp(endname - 13, "test.fail.dns") == 0) + { + DEBUG(D_dns) debug_printf("Return from DNS lookup of %s (%s) faked for testing\n", + name, dns_text_type(type)); + h_errno = NO_RECOVERY; + return -1; + } + +if (Ustrcmp(name, "test.ex") == 0 || + (len > 8 && Ustrcmp(endname - 8, ".test.ex") == 0) || + (len >= 16 && Ustrcmp(endname - 16, ".10.in-addr.arpa") == 0)) + { + uschar utilname[256]; + struct stat statbuf; + + (void)string_format(utilname, sizeof(utilname), "%s/../bin/fakens", + spool_directory); + + if (stat(CS utilname, &statbuf) >= 0) + { + pid_t pid; + int infd, outfd, rc; + uschar *argv[5]; + + DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) using fakens\n", + name, dns_text_type(type)); + + argv[0] = utilname; + argv[1] = spool_directory; + argv[2] = name; + argv[3] = dns_text_type(type); + argv[4] = NULL; + + pid = child_open(argv, NULL, 0000, &infd, &outfd, FALSE); + if (pid < 0) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to run fakens: %s", + strerror(errno)); + + len = 0; + rc = -1; + while (size > 0 && (rc = read(outfd, answerptr, size)) > 0) + { + len += rc; + answerptr += rc; + size -= rc; + } + + if (rc < 0) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "read from fakens failed: %s", + strerror(errno)); + + switch(child_close(pid, 0)) + { + case 0: return len; + case 1: h_errno = HOST_NOT_FOUND; break; + case 2: h_errno = TRY_AGAIN; break; + default: + case 3: h_errno = NO_RECOVERY; break; + case 4: h_errno = NO_DATA; break; + } + return -1; + } + } + +/* Not test.ex or 10.in-addr.arpa, or fakens utility not found. */ + +return res_search(CS name, C_IN, type, answerptr, size); +} + + /************************************************* * Initialize and configure resolver * @@ -334,8 +448,8 @@ Returns: DNS_SUCCEED successful lookup int dns_basic_lookup(dns_answer *dnsa, uschar *name, int type) { +int rc = -1; #ifndef STAND_ALONE -int rc; uschar *save; #endif @@ -361,35 +475,6 @@ if (previous != NULL) return previous->data.val; } -/* If we are running in the test harness, recognize a couple of special -names that always give error returns. This makes it straightforward to -test the handling of DNS errors. */ - -if (running_in_test_harness) - { - uschar *endname = name + Ustrlen(name); - if (Ustrcmp(endname - 14, "test.again.dns") == 0) - { - int delay = Uatoi(name); /* digits at the start of the name */ - DEBUG(D_dns) debug_printf("Real DNS lookup of %s (%s) bypassed for testing\n", - name, dns_text_type(type)); - if (delay > 0) - { - DEBUG(D_dns) debug_printf("delaying %d seconds\n", delay); - sleep(delay); - } - DEBUG(D_dns) debug_printf("returning DNS_AGAIN\n"); - return dns_return(name, type, DNS_AGAIN); - } - if (Ustrcmp(endname - 13, "test.fail.dns") == 0) - { - DEBUG(D_dns) debug_printf("Real DNS lookup of %s (%s) bypassed for testing\n", - name, dns_text_type(type)); - DEBUG(D_dns) debug_printf("returning DNS_FAIL\n"); - return dns_return(name, type, DNS_FAIL); - } - } - /* If configured, check the hygene of the name passed to lookup. Otherwise, although DNS lookups may give REFUSED at the lower level, some resolvers turn this into TRY_AGAIN, which is silly. Give a NOMATCH return, since such @@ -438,10 +523,18 @@ if (check_dns_names_pattern[0] != 0 && type != T_PTR) #endif /* STAND_ALONE */ /* Call the resolver; for an overlong response, res_search() will return the -number of bytes the message would need, so we need to check for this case. -The effect is to truncate overlong data. */ +number of bytes the message would need, so we need to check for this case. The +effect is to truncate overlong data. + +If we are running in the test harness, instead of calling the normal resolver +(res_search), we call fakens_search(), which recognizes certain special +domains, and interfaces to a fake nameserver for certain special zones. */ + +if (running_in_test_harness) + dnsa->answerlen = fakens_search(name, type, dnsa->answer, MAXPACKET); +else + dnsa->answerlen = res_search(CS name, C_IN, type, dnsa->answer, MAXPACKET); -dnsa->answerlen = res_search(CS name, C_IN, type, dnsa->answer, MAXPACKET); if (dnsa->answerlen > MAXPACKET) dnsa->answerlen = MAXPACKET; if (dnsa->answerlen < 0) switch (h_errno) |