diff options
| -rw-r--r-- | driver.c | 68 |
1 files changed, 38 insertions, 30 deletions
@@ -100,6 +100,7 @@ static int is_host_alias(const char *name, struct query *ctl) /* determine whether name is a DNS alias of the hostname */ { struct hostent *he; + struct mxentry *mxp, *mxrecords; int i; /* @@ -125,39 +126,46 @@ static int is_host_alias(const char *name, struct query *ctl) * delivering the current message or anything else from this * mailbox until it's back up. */ - else if ((he = gethostbyname(name)) == (struct hostent *)NULL) - longjmp(restart, 2); - - /* DNS response is OK */ - else if (strcmp(ctl->canonical_name, he->h_name) == 0) - return(TRUE); + else if ((he = gethostbyname(name)) != (struct hostent *)NULL) + return(strcmp(ctl->canonical_name, he->h_name) == 0); + else + switch (h_errno) + { + case HOST_NOT_FOUND: /* specified host is unknown */ + case NO_ADDRESS: /* valid, but does not have an IP address */ + break; + + case NO_RECOVERY: /* non-recoverable name server error */ + case TRY_AGAIN: /* temporary error on authoritative server */ + default: + longjmp(restart, 2); /* try again next poll cycle */ + break; + } /* - * Search for a name match on MX records pointing to the server - * site. These may live far away, so allow a couple of retries. + * We're only here if DNS was OK but the gethostbyname() failed + * with a HOST_NOT_FOUND or NO_ADDRESS error. + * Search for a name match on MX records pointing to the server. */ - for (i = 0; i < MX_RETRIES; i++) - { - struct mxentry *mxrecords, *mxp; - - mxrecords = getmxrecords(name); - - h_errno = 0; - if (mxrecords == (struct mxentry *)NULL) - if (h_errno == TRY_AGAIN) - { - sleep(1); - continue; - } - else if (h_errno) /* fatal error */ - longjmp(restart, 2); - else - break; - - for (mxp = mxrecords; mxp->name; mxp++) - if (strcmp(name, mxp->name) == 0) - return(TRUE); - } + h_errno = 0; + if ((mxrecords = getmxrecords(name)) == (struct mxentry *)NULL) + switch (h_errno) + { + case HOST_NOT_FOUND: /* specified host is unknown */ + return(FALSE); + + case NO_ADDRESS: /* valid, but does not have an IP address */ + for (mxp = mxrecords; mxp->name; mxp++) + if (strcmp(name, mxp->name) == 0) + return(TRUE); + break; + + case NO_RECOVERY: /* non-recoverable name server error */ + case TRY_AGAIN: /* temporary error on authoritative server */ + default: + longjmp(restart, 2); /* try again next poll cycle */ + break; + } return(FALSE); } |