ares_gethostbyname.c File Reference

#include "ares_private.h"

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Data Structures
struct	host_query
Functions
void	next_lookup (struct host_query *hquery)
void	host_callback (void *arg, int status, unsigned char *abuf, int alen)
void	end_hquery (struct host_query *hquery, int status, struct hostent *host)
int	fake_hostent (const char *name, ares_host_callback callback, void *arg)
void	sort_addresses (struct hostent *host, struct apattern *sortlist, int nsort)
int	get_address_index (struct in_addr *addr, struct apattern *sortlist, int nsort)
void	ares_gethostbyname (ares_channel channel, const char *name, int family, ares_host_callback callback, void *arg)

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Function Documentation

void ares_gethostbyname (  ares_channel  channel, const char *  name, int  family, ares_host_callback  callback, void *  arg )

Definition at line 47 of file ares_gethostbyname.c. References AF_INET, ares_channel, ARES_ENOMEM, ARES_ENOTIMP, ares_host_callback, callback(), fake_hostent(), free, ares_channeldata::lookups, malloc, name, next_lookup(), NULL, and strdup. Referenced by dns_client(), and gethostbynameaddr(). { struct host_query *hquery; /* Right now we only know how to look up Internet addresses. */ if (family != AF_INET) { callback(arg, ARES_ENOTIMP, NULL); return; } if (fake_hostent(name, callback, arg)) return; /* Allocate and fill in the host query structure. */ hquery = malloc(sizeof(struct host_query)); if (!hquery) { callback(arg, ARES_ENOMEM, NULL); return; } hquery->channel = channel; hquery->name = strdup(name); if (!hquery->name) { free(hquery); callback(arg, ARES_ENOMEM, NULL); return; } hquery->callback = callback; hquery->arg = arg; hquery->remaining_lookups = channel->lookups; /* Start performing lookups according to channel->lookups. */ next_lookup(hquery); }

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void end_hquery (  struct host_query *  hquery, int  status, struct hostent *  host )  [static]

Definition at line 129 of file ares_gethostbyname.c. References ares_free_hostent(), host_query::arg, host_query::callback, free, host_query::name, and status. Referenced by host_callback(), and next_lookup(). { hquery->callback(hquery->arg, status, host); if (host) ares_free_hostent(host); free(hquery->name); free(hquery); }

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int fake_hostent (  const char *  name, ares_host_callback  callback, void *  arg )  [static]

Definition at line 142 of file ares_gethostbyname.c. References AF_INET, ARES_EBADNAME, ARES_ENOMEM, ares_host_callback, ARES_SUCCESS, callback(), free, hostent::h_addr_list, hostent::h_addrtype, hostent::h_aliases, hostent::h_length, hostent::h_name, INADDR_NONE, inet_addr(), name, NULL, in_addr::s_addr, and strdup. Referenced by ares_gethostbyname(). { struct in_addr addr; struct hostent hostent; const char *p; char *aliases[1] = { NULL }; char *addrs[2]; /* It only looks like an IP address if it's all numbers and dots. */ for (p = name; *p; p++) { if (!isdigit((unsigned char)*p) && *p != '.') return 0; } /* It also only looks like an IP address if it's non-zero-length and * doesn't end with a dot. */ if (p == name || *(p - 1) == '.') return 0; /* It looks like an IP address. Figure out what IP address it is. */ addr.s_addr = inet_addr(name); if (addr.s_addr == INADDR_NONE) { callback(arg, ARES_EBADNAME, NULL); return 1; } /* Duplicate the name, to avoid a constness violation. */ hostent.h_name = strdup(name); if (!hostent.h_name) { callback(arg, ARES_ENOMEM, NULL); return 1; } /* Fill in the rest of the host structure and terminate the query. */ addrs[0] = (char *) &addr; addrs[1] = NULL; hostent.h_aliases = aliases; hostent.h_addrtype = AF_INET; hostent.h_length = sizeof(struct in_addr); hostent.h_addr_list = addrs; callback(arg, ARES_SUCCESS, &hostent); free(hostent.h_name); return 1; }

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int get_address_index (  struct in_addr *  addr, struct apattern *  sortlist, int  nsort )  [static]

Definition at line 223 of file ares_gethostbyname.c. References apattern::addr, apattern::mask, and in_addr::s_addr. Referenced by sort_addresses(). { int i; for (i = 0; i < nsort; i++) { if ((addr->s_addr & sortlist[i].mask.s_addr) == sortlist[i].addr.s_addr) break; } return i; }

void host_callback (  void *  arg, int  status, unsigned char *  abuf, int  alen )  [static]

Definition at line 110 of file ares_gethostbyname.c. References ares_channel, ARES_EDESTRUCTION, ares_parse_a_reply(), ARES_SUCCESS, end_hquery(), next_lookup(), ares_channeldata::nsort, NULL, sort_addresses(), ares_channeldata::sortlist, and status. Referenced by next_lookup(). { struct host_query *hquery = (struct host_query *) arg; ares_channel channel = hquery->channel; struct hostent *host; if (status == ARES_SUCCESS) { status = ares_parse_a_reply(abuf, alen, &host); if (host && channel->nsort) sort_addresses(host, channel->sortlist, channel->nsort); end_hquery(hquery, status, host); } else if (status == ARES_EDESTRUCTION) end_hquery(hquery, status, NULL); else next_lookup(hquery); }

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void next_lookup (  struct host_query *  hquery  )  [static]

Definition at line 87 of file ares_gethostbyname.c. References ARES_ENOTFOUND, ares_search(), C_IN, host_query::channel, end_hquery(), host_callback(), host_query::name, NULL, host_query::remaining_lookups, and T_A. Referenced by addr_callback(), ares_gethostbyaddr(), ares_gethostbyname(), and host_callback(). { const char *p; for (p = hquery->remaining_lookups; *p; p++) { switch (*p) { case 'b': /* DNS lookup */ hquery->remaining_lookups = p + 1; ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback, hquery); return; case 'f': /* Host file lookup */ break; } } end_hquery(hquery, ARES_ENOTFOUND, NULL); }

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void sort_addresses (  struct hostent *  host, struct apattern *  sortlist, int  nsort )  [static]

Definition at line 193 of file ares_gethostbyname.c. References get_address_index(), and hostent::h_addr_list. Referenced by host_callback(). { struct in_addr a1, a2; int i1, i2, ind1, ind2; /* This is a simple insertion sort, not optimized at all. i1 walks * through the address list, with the loop invariant that everything * to the left of i1 is sorted. In the loop body, the value at i1 is moved * back through the list (via i2) until it is in sorted order. */ for (i1 = 0; host->h_addr_list[i1]; i1++) { memcpy(&a1, host->h_addr_list[i1], sizeof(struct in_addr)); ind1 = get_address_index(&a1, sortlist, nsort); for (i2 = i1 - 1; i2 >= 0; i2--) { memcpy(&a2, host->h_addr_list[i2], sizeof(struct in_addr)); ind2 = get_address_index(&a2, sortlist, nsort); if (ind2 <= ind1) break; memcpy(host->h_addr_list[i2 + 1], &a2, sizeof(struct in_addr)); } memcpy(host->h_addr_list[i2 + 1], &a1, sizeof(struct in_addr)); } }

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