ares.h File Reference

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	ares_options
Defines
#define	ARES_SUCCESS   0
#define	ARES_ENODATA   1
#define	ARES_EFORMERR   2
#define	ARES_ESERVFAIL   3
#define	ARES_ENOTFOUND   4
#define	ARES_ENOTIMP   5
#define	ARES_EREFUSED   6
#define	ARES_EBADQUERY   7
#define	ARES_EBADNAME   8
#define	ARES_EBADFAMILY   9
#define	ARES_EBADRESP   10
#define	ARES_ECONNREFUSED   11
#define	ARES_ETIMEOUT   12
#define	ARES_EOF   13
#define	ARES_EFILE   14
#define	ARES_ENOMEM   15
#define	ARES_EDESTRUCTION   16
#define	ARES_FLAG_USEVC   (1 << 0)
#define	ARES_FLAG_PRIMARY   (1 << 1)
#define	ARES_FLAG_IGNTC   (1 << 2)
#define	ARES_FLAG_NORECURSE   (1 << 3)
#define	ARES_FLAG_STAYOPEN   (1 << 4)
#define	ARES_FLAG_NOSEARCH   (1 << 5)
#define	ARES_FLAG_NOALIASES   (1 << 6)
#define	ARES_FLAG_NOCHECKRESP   (1 << 7)
#define	ARES_OPT_FLAGS   (1 << 0)
#define	ARES_OPT_TIMEOUT   (1 << 1)
#define	ARES_OPT_TRIES   (1 << 2)
#define	ARES_OPT_NDOTS   (1 << 3)
#define	ARES_OPT_UDP_PORT   (1 << 4)
#define	ARES_OPT_TCP_PORT   (1 << 5)
#define	ARES_OPT_SERVERS   (1 << 6)
#define	ARES_OPT_DOMAINS   (1 << 7)
#define	ARES_OPT_LOOKUPS   (1 << 8)
Typedefs
typedef ares_channeldata *	ares_channel
typedef void(*	ares_callback )(void *arg, int status, unsigned char *abuf, int alen)
typedef void(*	ares_host_callback )(void *arg, int status, struct hostent *hostent)
Functions
int	ares_init (ares_channel *channelptr)
int	ares_init_options (ares_channel *channelptr, struct ares_options *options, int optmask)
void	ares_destroy (ares_channel channel)
void	ares_send (ares_channel channel, const unsigned char *qbuf, int qlen, ares_callback callback, void *arg)
void	ares_query (ares_channel channel, const char *name, int dnsclass, int type, ares_callback callback, void *arg)
void	ares_search (ares_channel channel, const char *name, int dnsclass, int type, ares_callback callback, void *arg)
void	ares_gethostbyname (ares_channel channel, const char *name, int family, ares_host_callback callback, void *arg)
void	ares_gethostbyaddr (ares_channel channel, const void *addr, int addrlen, int family, ares_host_callback callback, void *arg)
int	ares_fds (ares_channel channel, fd_set *read_fds, fd_set *write_fds)
timeval *	ares_timeout (ares_channel channel, struct timeval *maxtv, struct timeval *tv)
void	ares_process (ares_channel channel, fd_set *read_fds, fd_set *write_fds)
int	ares_mkquery (const char *name, int dnsclass, int type, unsigned short id, int rd, unsigned char **buf, int *buflen)
int	ares_expand_name (const unsigned char *encoded, const unsigned char *abuf, int alen, char **s, int *enclen)
int	ares_parse_a_reply (const unsigned char *abuf, int alen, struct hostent **host)
int	ares_parse_ptr_reply (const unsigned char *abuf, int alen, const void *addr, int addrlen, int family, struct hostent **host)
void	ares_free_string (unsigned char *str)
void	ares_free_hostent (struct hostent *host)
const char *	ares_strerror (int code, char **memptr)
void	ares_free_errmem (char *mem)

---

Define Documentation

#define ARES_EBADFAMILY   9

Definition at line 41 of file ares.h.

#define ARES_EBADNAME   8

Definition at line 40 of file ares.h. Referenced by ares_expand_name(), ares_mkquery(), and fake_hostent().

#define ARES_EBADQUERY   7

Definition at line 39 of file ares.h. Referenced by ares_send().

#define ARES_EBADRESP   10

Definition at line 42 of file ares.h. Referenced by ares_parse_a_reply(), and ares_parse_ptr_reply().

#define ARES_ECONNREFUSED   11

Definition at line 43 of file ares.h. Referenced by ares_send().

#define ARES_EDESTRUCTION   16

Definition at line 48 of file ares.h. Referenced by addr_callback(), ares_destroy(), and host_callback().

#define ARES_EFILE   14

Definition at line 46 of file ares.h.

#define ARES_EFORMERR   2

Definition at line 32 of file ares.h. Referenced by qcallback().

#define ARES_ENODATA   1

Definition at line 31 of file ares.h. Referenced by ares_parse_a_reply(), ares_parse_ptr_reply(), qcallback(), and search_callback().

#define ARES_ENOMEM   15

Definition at line 47 of file ares.h. Referenced by ares__send_query(), ares_expand_name(), ares_gethostbyaddr(), ares_gethostbyname(), ares_init_options(), ares_mkquery(), ares_parse_a_reply(), ares_parse_ptr_reply(), ares_query(), ares_search(), ares_send(), cat_domain(), fake_hostent(), init_by_defaults(), init_by_options(), and single_domain().

#define ARES_ENOTFOUND   4

Definition at line 34 of file ares.h. Referenced by gethostbynameaddr(), next_lookup(), qcallback(), and search_callback().

#define ARES_ENOTIMP   5

Definition at line 35 of file ares.h. Referenced by ares_gethostbyaddr(), ares_gethostbyname(), and qcallback().

#define ARES_EOF   13

Definition at line 45 of file ares.h.

#define ARES_EREFUSED   6

Definition at line 36 of file ares.h. Referenced by qcallback().

#define ARES_ESERVFAIL   3

Definition at line 33 of file ares.h. Referenced by qcallback(), and search_callback().

#define ARES_ETIMEOUT   12

Definition at line 44 of file ares.h. Referenced by process_timeouts().

#define ARES_FLAG_IGNTC   (1 << 2)

Definition at line 53 of file ares.h. Referenced by process_answer().

#define ARES_FLAG_NOALIASES   (1 << 6)

Definition at line 57 of file ares.h.

#define ARES_FLAG_NOCHECKRESP   (1 << 7)

Definition at line 58 of file ares.h. Referenced by process_answer().

#define ARES_FLAG_NORECURSE   (1 << 3)

Definition at line 54 of file ares.h. Referenced by ares_query().

#define ARES_FLAG_NOSEARCH   (1 << 5)

Definition at line 56 of file ares.h. Referenced by single_domain().

#define ARES_FLAG_PRIMARY   (1 << 1)

Definition at line 52 of file ares.h. Referenced by ares_init_options().

#define ARES_FLAG_STAYOPEN   (1 << 4)

Definition at line 55 of file ares.h. Referenced by end_query().

#define ARES_FLAG_USEVC   (1 << 0)

Definition at line 51 of file ares.h. Referenced by ares_send(), and dns_client().

#define ARES_OPT_DOMAINS   (1 << 7)

Definition at line 68 of file ares.h. Referenced by init_by_options().

#define ARES_OPT_FLAGS   (1 << 0)

Definition at line 61 of file ares.h. Referenced by dns_client(), and init_by_options().

#define ARES_OPT_LOOKUPS   (1 << 8)

Definition at line 69 of file ares.h. Referenced by init_by_options().

#define ARES_OPT_NDOTS   (1 << 3)

Definition at line 64 of file ares.h. Referenced by init_by_options().

#define ARES_OPT_SERVERS   (1 << 6)

Definition at line 67 of file ares.h. Referenced by dns_client(), gethostbynameaddr(), and init_by_options().

#define ARES_OPT_TCP_PORT   (1 << 5)

Definition at line 66 of file ares.h. Referenced by init_by_options().

#define ARES_OPT_TIMEOUT   (1 << 1)

Definition at line 62 of file ares.h. Referenced by init_by_options().

#define ARES_OPT_TRIES   (1 << 2)

Definition at line 63 of file ares.h. Referenced by init_by_options().

#define ARES_OPT_UDP_PORT   (1 << 4)

Definition at line 65 of file ares.h. Referenced by init_by_options().

#define ARES_SUCCESS   0

Definition at line 28 of file ares.h. Referenced by addr_callback(), ares_expand_name(), ares_init_options(), ares_mkquery(), ares_parse_a_reply(), ares_parse_ptr_reply(), ares_query(), ares_search(), callback(), cat_domain(), dns_client(), dns_client_callback(), fake_hostent(), gethostbynameaddr(), host_callback(), init_by_defaults(), init_by_options(), process_answer(), qcallback(), same_questions(), search_callback(), and single_domain().

---

Typedef Documentation

typedef void(* ares_callback)(void *arg, int status, unsigned char *abuf, int alen)

Definition at line 87 of file ares.h. Referenced by ares_query(), ares_search(), and ares_send().

typedef struct ares_channeldata* ares_channel

Definition at line 86 of file ares.h. Referenced by ares__send_query(), ares_destroy(), ares_fds(), ares_gethostbyaddr(), ares_gethostbyname(), ares_init(), ares_init_options(), ares_process(), ares_query(), ares_search(), ares_send(), ares_timeout(), dns_client(), end_query(), gethostbynameaddr(), handle_error(), host_callback(), init_by_defaults(), init_by_options(), next_server(), open_tcp_socket(), open_udp_socket(), process_answer(), process_timeouts(), read_tcp_data(), read_udp_packets(), search_callback(), single_domain(), and write_tcp_data().

typedef void(* ares_host_callback)(void *arg, int status, struct hostent *hostent)

Definition at line 89 of file ares.h. Referenced by ares_gethostbyaddr(), ares_gethostbyname(), and fake_hostent().

---

Function Documentation

void ares_destroy (  ares_channel  channel  )

Definition at line 25 of file ares_destroy.c. References ares__close_sockets(), ares_channel, ARES_EDESTRUCTION, query::callback, ares_channeldata::domains, free, ares_channeldata::lookups, ares_channeldata::ndomains, query::next, ares_channeldata::nservers, NULL, ares_channeldata::queries, ares_channeldata::servers, and ares_channeldata::sortlist. Referenced by dns_client(), and gethostbynameaddr(). { int i; struct query *query; for (i = 0; i < channel->nservers; i++) ares__close_sockets(&channel->servers[i]); free(channel->servers); for (i = 0; i < channel->ndomains; i++) free(channel->domains[i]); free(channel->domains); free(channel->sortlist); free(channel->lookups); while (channel->queries) { query = channel->queries; channel->queries = query->next; query->callback(query->arg, ARES_EDESTRUCTION, NULL, 0); free(query->tcpbuf); free(query->skip_server); free(query); } free(channel); }

Here is the call graph for this function:

int ares_expand_name (  const unsigned char *  encoded, const unsigned char *  abuf, int  alen, char **  s, int *  enclen )

Definition at line 52 of file ares_expand_name.c. References ARES_EBADNAME, ARES_ENOMEM, ARES_SUCCESS, INDIR_MASK, len, malloc, and name_length(). Referenced by ares_parse_a_reply(), ares_parse_ptr_reply(), and same_questions(). { int len, indir = 0; char *q; const unsigned char *p; len = name_length(encoded, abuf, alen); if (len == -1) return ARES_EBADNAME; *s = malloc(len + 1); if (!*s) return ARES_ENOMEM; q = *s; /* No error-checking necessary; it was all done by name_length(). */ p = encoded; while (*p) { if ((*p & INDIR_MASK) == INDIR_MASK) { if (!indir) { *enclen = p + 2 - encoded; indir = 1; } p = abuf + ((*p & ~INDIR_MASK) << 8 | *(p + 1)); } else { len = *p; p++; while (len--) { if (*p == '.' || *p == '\\') *q++ = '\\'; *q++ = *p; p++; } *q++ = '.'; } } if (!indir) *enclen = p + 1 - encoded; /* Nuke the trailing period if we wrote one. */ if (q > *s) *(q - 1) = 0; return ARES_SUCCESS; }

Here is the call graph for this function:

int ares_fds (  ares_channel  channel, fd_set *  read_fds, fd_set *  write_fds )

Definition at line 25 of file ares_fds.c. References ares_channel, FD_SET, ares_channeldata::nservers, ares_channeldata::queries, and ares_channeldata::servers. Referenced by dns_client(), and gethostbynameaddr(). { struct server_state *server; int i, nfds; /* No queries, no file descriptors. */ if (!channel->queries) return 0; nfds = 0; for (i = 0; i < channel->nservers; i++) { server = &channel->servers[i]; if (server->udp_socket != -1) { FD_SET(server->udp_socket, read_fds); if (server->udp_socket >= nfds) nfds = server->udp_socket + 1; } if (server->tcp_socket != -1) { FD_SET(server->tcp_socket, read_fds); if (server->qhead) FD_SET(server->tcp_socket, write_fds); if (server->tcp_socket >= nfds) nfds = server->tcp_socket + 1; } } return nfds; }

void ares_free_errmem (  char *  mem  )

Definition at line 29 of file ares_free_errmem.c. Referenced by dns_client(), and dns_client_callback(). { (void) mem; }

void ares_free_hostent (  struct hostent *  host  )

Definition at line 25 of file ares_free_hostent.c. References free, hostent::h_addr_list, hostent::h_aliases, and hostent::h_name. Referenced by end_aquery(), and end_hquery(). { char **p; free(host->h_name); for (p = host->h_aliases; *p; p++) free(*p); free(host->h_aliases); free(host->h_addr_list[0]); free(host->h_addr_list); free(host); }

void ares_free_string (  unsigned char *  str  )

Definition at line 25 of file ares_free_string.c. References free. Referenced by ares_query(). { free(str); }

void ares_gethostbyaddr (  ares_channel  channel, const void *  addr, int  addrlen, int  family, ares_host_callback  callback, void *  arg )

Definition at line 46 of file ares_gethostbyaddr.c. References AF_INET, ares_channel, ARES_ENOMEM, ARES_ENOTIMP, ares_host_callback, callback(), ares_channeldata::lookups, malloc, next_lookup(), and NULL. Referenced by dns_client(), and gethostbynameaddr(). { struct addr_query *aquery; if (family != AF_INET || addrlen != sizeof(struct in_addr)) { callback(arg, ARES_ENOTIMP, NULL); return; } aquery = malloc(sizeof(struct addr_query)); if (!aquery) { callback(arg, ARES_ENOMEM, NULL); return; } aquery->channel = channel; memcpy(&aquery->addr, addr, sizeof(aquery->addr)); aquery->callback = callback; aquery->arg = arg; aquery->remaining_lookups = channel->lookups; next_lookup(aquery); }

Here is the call graph for this function:

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); }

Here is the call graph for this function:

int ares_init (  ares_channel *  channelptr  )

Definition at line 34 of file ares_init.c. References ares_channel, ares_init_options(), and NULL. { return ares_init_options(channelptr, NULL, 0); }

Here is the call graph for this function:

int ares_init_options (  ares_channel *  channelptr, struct ares_options *  options, int  optmask )

Definition at line 40 of file ares_init.c. References ares_channel, ARES_ENOMEM, ARES_FLAG_PRIMARY, ARES_SUCCESS, ares_channeldata::domains, ares_channeldata::flags, free, gettimeofday(), init_by_defaults(), init_by_options(), ares_channeldata::lookups, malloc, ares_channeldata::ndomains, ares_channeldata::ndots, ares_channeldata::next_id, ares_channeldata::nservers, ares_channeldata::nsort, NULL, ares_channeldata::queries, ares_channeldata::servers, ares_channeldata::sortlist, status, ares_channeldata::tcp_port, time, ares_channeldata::timeout, ares_channeldata::tries, ares_channeldata::udp_port, and server_state::udp_socket. Referenced by ares_init(), dns_client(), and gethostbynameaddr(). { ares_channel channel; int i, status; struct server_state *server; channel = malloc(sizeof(struct ares_channeldata)); if (!channel) return ARES_ENOMEM; /* Set everything to distinguished values so we know they haven't * been set yet. */ channel->flags = -1; channel->timeout = -1; channel->tries = -1; channel->ndots = -1; channel->udp_port = -1; channel->tcp_port = -1; channel->nservers = -1; channel->ndomains = -1; channel->nsort = -1; channel->lookups = NULL; /* Initialize configuration by each of the four sources, from highest * precedence to lowest. */ status = init_by_options(channel, options, optmask); if (status == ARES_SUCCESS) status = init_by_defaults(channel); if (status != ARES_SUCCESS) { /* Something failed; clean up memory we may have allocated. */ if (channel->nservers != -1) free(channel->servers); if (channel->ndomains != -1) { for (i = 0; i < channel->ndomains; i++) free(channel->domains[i]); free(channel->domains); } if (channel->nsort != -1) free(channel->sortlist); free(channel->lookups); free(channel); return status; } /* Trim to one server if ARES_FLAG_PRIMARY is set. */ if ((channel->flags & ARES_FLAG_PRIMARY) && channel->nservers > 1) channel->nservers = 1; /* Initialize server states. */ for (i = 0; i < channel->nservers; i++) { server = &channel->servers[i]; server->udp_socket = -1; server->tcp_socket = -1; server->tcp_lenbuf_pos = 0; server->tcp_buffer = NULL; server->qhead = NULL; server->qtail = NULL; } /* Choose a somewhat random query ID. The main point is to avoid * collisions with stale queries. An attacker trying to spoof a DNS * answer also has to guess the query ID, but it's only a 16-bit * field, so there's not much to be done about that. */ // channel->next_id = (RetrieveClock() ^ os_current_process()) & 0xffff; { struct timeval time; gettimeofday(&time,NULL); channel->next_id = (time.tv_usec ^ time.tv_sec) & 0xffff; } channel->queries = NULL; *channelptr = channel; return ARES_SUCCESS; }

Here is the call graph for this function:

int ares_mkquery (  const char *  name, int  dnsclass, int  type, unsigned short  id, int  rd, unsigned char **  buf, int *  buflen )

Definition at line 74 of file ares_mkquery.c. References ARES_EBADNAME, ARES_ENOMEM, ARES_SUCCESS, DNS_HEADER_SET_OPCODE, DNS_HEADER_SET_QDCOUNT, DNS_HEADER_SET_QID, DNS_HEADER_SET_RD, DNS_QUESTION_SET_CLASS, DNS_QUESTION_SET_TYPE, HFIXEDSZ, len, malloc, MAXLABEL, name, QFIXEDSZ, and QUERY. Referenced by ares_query(). { int len; unsigned char *q; const char *p; /* Compute the length of the encoded name so we can check buflen. * Start counting at 1 for the zero-length label at the end. */ len = 1; for (p = name; *p; p++) { if (*p == '\\' && *(p + 1) != 0) p++; len++; } /* If there are n periods in the name, there are n + 1 labels, and * thus n + 1 length fields, unless the name is empty or ends with a * period. So add 1 unless name is empty or ends with a period. */ if (*name && *(p - 1) != '.') len++; *buflen = len + HFIXEDSZ + QFIXEDSZ; *buf = malloc(*buflen); if (!*buf) return ARES_ENOMEM; /* Set up the header. */ q = *buf; memset(q, 0, HFIXEDSZ); DNS_HEADER_SET_QID(q, id); DNS_HEADER_SET_OPCODE(q, QUERY); DNS_HEADER_SET_RD(q, (rd) ? 1 : 0); DNS_HEADER_SET_QDCOUNT(q, 1); /* A name of "." is a screw case for the loop below, so adjust it. */ if (strcmp(name, ".") == 0) name++; /* Start writing out the name after the header. */ q += HFIXEDSZ; while (*name) { if (*name == '.') return ARES_EBADNAME; /* Count the number of bytes in this label. */ len = 0; for (p = name; *p && *p != '.'; p++) { if (*p == '\\' && *(p + 1) != 0) p++; len++; } if (len > MAXLABEL) return ARES_EBADNAME; /* Encode the length and copy the data. */ *q++ = len; for (p = name; *p && *p != '.'; p++) { if (*p == '\\' && *(p + 1) != 0) p++; *q++ = *p; } /* Go to the next label and repeat, unless we hit the end. */ if (!*p) break; name = p + 1; } /* Add the zero-length label at the end. */ *q++ = 0; /* Finish off the question with the type and class. */ DNS_QUESTION_SET_TYPE(q, type); DNS_QUESTION_SET_CLASS(q, dnsclass); return ARES_SUCCESS; }

int ares_parse_a_reply (  const unsigned char *  abuf, int  alen, struct hostent **  host )

Definition at line 26 of file ares_parse_a_reply.c. References AF_INET, ARES_EBADRESP, ARES_ENODATA, ARES_ENOMEM, ares_expand_name(), ARES_SUCCESS, C_IN, DNS_HEADER_ANCOUNT, DNS_HEADER_QDCOUNT, DNS_RR_CLASS, DNS_RR_LEN, DNS_RR_TYPE, free, HFIXEDSZ, len, malloc, NULL, QFIXEDSZ, RRFIXEDSZ, status, strcasecmp, T_A, and T_CNAME. Referenced by host_callback(). { unsigned int qdcount, ancount; int status, i, len, rr_type, rr_class, rr_len, naddrs; int naliases; const unsigned char *aptr; char *hostname, *rr_name, *rr_data, **aliases; struct in_addr *addrs; struct hostent *hostent; /* Set *host to NULL for all failure cases. */ *host = NULL; /* Give up if abuf doesn't have room for a header. */ if (alen < HFIXEDSZ) return ARES_EBADRESP; /* Fetch the question and answer count from the header. */ qdcount = DNS_HEADER_QDCOUNT(abuf); ancount = DNS_HEADER_ANCOUNT(abuf); if (qdcount != 1) return ARES_EBADRESP; /* Expand the name from the question, and skip past the question. */ aptr = abuf + HFIXEDSZ; status = ares_expand_name(aptr, abuf, alen, &hostname, &len); if (status != ARES_SUCCESS) return status; if (aptr + len + QFIXEDSZ > abuf + alen) { free(hostname); return ARES_EBADRESP; } aptr += len + QFIXEDSZ; /* Allocate addresses and aliases; ancount gives an upper bound for both. */ addrs = malloc(ancount * sizeof(struct in_addr)); if (!addrs) { free(hostname); return ARES_ENOMEM; } aliases = malloc((ancount + 1) * sizeof(char *)); if (!aliases) { free(hostname); free(addrs); return ARES_ENOMEM; } naddrs = 0; naliases = 0; /* Examine each answer resource record (RR) in turn. */ for (i = 0; i < ancount; i++) { /* Decode the RR up to the data field. */ status = ares_expand_name(aptr, abuf, alen, &rr_name, &len); if (status != ARES_SUCCESS) break; aptr += len; if (aptr + RRFIXEDSZ > abuf + alen) { status = ARES_EBADRESP; break; } rr_type = DNS_RR_TYPE(aptr); rr_class = DNS_RR_CLASS(aptr); rr_len = DNS_RR_LEN(aptr); aptr += RRFIXEDSZ; if (rr_class == C_IN && rr_type == T_A && rr_len == sizeof(struct in_addr) && strcasecmp(rr_name, hostname) == 0) { memcpy(&addrs[naddrs], aptr, sizeof(struct in_addr)); naddrs++; status = ARES_SUCCESS; } if (rr_class == C_IN && rr_type == T_CNAME) { /* Record the RR name as an alias. */ aliases[naliases] = rr_name; naliases++; /* Decode the RR data and replace the hostname with it. */ status = ares_expand_name(aptr, abuf, alen, &rr_data, &len); if (status != ARES_SUCCESS) break; free(hostname); hostname = rr_data; } else free(rr_name); aptr += rr_len; if (aptr > abuf + alen) { status = ARES_EBADRESP; break; } } if (status == ARES_SUCCESS && naddrs == 0) status = ARES_ENODATA; if (status == ARES_SUCCESS) { /* We got our answer. Allocate memory to build the host entry. */ aliases[naliases] = NULL; hostent = malloc(sizeof(struct hostent)); if (hostent) { hostent->h_addr_list = malloc((naddrs + 1) * sizeof(char *)); if (hostent->h_addr_list) { /* Fill in the hostent and return successfully. */ hostent->h_name = hostname; hostent->h_aliases = aliases; hostent->h_addrtype = AF_INET; hostent->h_length = sizeof(struct in_addr); for (i = 0; i < naddrs; i++) hostent->h_addr_list[i] = (char *) &addrs[i]; hostent->h_addr_list[naddrs] = NULL; *host = hostent; return ARES_SUCCESS; } free(hostent); } status = ARES_ENOMEM; } for (i = 0; i < naliases; i++) free(aliases[i]); free(aliases); free(addrs); free(hostname); return status; }

Here is the call graph for this function:

int ares_parse_ptr_reply (  const unsigned char *  abuf, int  alen, const void *  addr, int  addrlen, int  family, struct hostent **  host )

Definition at line 26 of file ares_parse_ptr_reply.c. References ARES_EBADRESP, ARES_ENODATA, ARES_ENOMEM, ares_expand_name(), ARES_SUCCESS, C_IN, DNS_HEADER_ANCOUNT, DNS_HEADER_QDCOUNT, DNS_RR_CLASS, DNS_RR_LEN, DNS_RR_TYPE, free, HFIXEDSZ, len, malloc, NULL, QFIXEDSZ, RRFIXEDSZ, status, strcasecmp, T_CNAME, and T_PTR. Referenced by addr_callback(). { unsigned int qdcount, ancount; int status, i, len, rr_type, rr_class, rr_len; const unsigned char *aptr; char *ptrname, *hostname, *rr_name, *rr_data; struct hostent *hostent; /* Set *host to NULL for all failure cases. */ *host = NULL; /* Give up if abuf doesn't have room for a header. */ if (alen < HFIXEDSZ) return ARES_EBADRESP; /* Fetch the question and answer count from the header. */ qdcount = DNS_HEADER_QDCOUNT(abuf); ancount = DNS_HEADER_ANCOUNT(abuf); if (qdcount != 1) return ARES_EBADRESP; /* Expand the name from the question, and skip past the question. */ aptr = abuf + HFIXEDSZ; status = ares_expand_name(aptr, abuf, alen, &ptrname, &len); if (status != ARES_SUCCESS) return status; if (aptr + len + QFIXEDSZ > abuf + alen) { free(ptrname); return ARES_EBADRESP; } aptr += len + QFIXEDSZ; /* Examine each answer resource record (RR) in turn. */ hostname = NULL; for (i = 0; i < ancount; i++) { /* Decode the RR up to the data field. */ status = ares_expand_name(aptr, abuf, alen, &rr_name, &len); if (status != ARES_SUCCESS) break; aptr += len; if (aptr + RRFIXEDSZ > abuf + alen) { status = ARES_EBADRESP; break; } rr_type = DNS_RR_TYPE(aptr); rr_class = DNS_RR_CLASS(aptr); rr_len = DNS_RR_LEN(aptr); aptr += RRFIXEDSZ; if (rr_class == C_IN && rr_type == T_PTR && strcasecmp(rr_name, ptrname) == 0) { /* Decode the RR data and set hostname to it. */ status = ares_expand_name(aptr, abuf, alen, &rr_data, &len); if (status != ARES_SUCCESS) break; if (hostname) free(hostname); hostname = rr_data; } if (rr_class == C_IN && rr_type == T_CNAME) { /* Decode the RR data and replace ptrname with it. */ status = ares_expand_name(aptr, abuf, alen, &rr_data, &len); if (status != ARES_SUCCESS) break; free(ptrname); ptrname = rr_data; } free(rr_name); aptr += rr_len; if (aptr > abuf + alen) { status = ARES_EBADRESP; break; } } if (status == ARES_SUCCESS && !hostname) status = ARES_ENODATA; if (status == ARES_SUCCESS) { /* We got our answer. Allocate memory to build the host entry. */ hostent = malloc(sizeof(struct hostent)); if (hostent) { hostent->h_addr_list = malloc(2 * sizeof(char *)); if (hostent->h_addr_list) { hostent->h_addr_list[0] = malloc(addrlen); if (hostent->h_addr_list[0]) { hostent->h_aliases = malloc(sizeof (char *)); if (hostent->h_aliases) { /* Fill in the hostent and return successfully. */ hostent->h_name = hostname; hostent->h_aliases[0] = NULL; hostent->h_addrtype = family; hostent->h_length = addrlen; memcpy(hostent->h_addr_list[0], addr, addrlen); hostent->h_addr_list[1] = NULL; *host = hostent; free(ptrname); return ARES_SUCCESS; } free(hostent->h_addr_list[0]); } free(hostent->h_addr_list); } free(hostent); } status = ARES_ENOMEM; } if (hostname) free(hostname); free(ptrname); return status; }

Here is the call graph for this function:

void ares_process (  ares_channel  channel, fd_set *  read_fds, fd_set *  write_fds )

Definition at line 46 of file ares_process.c. References ares_channel, process_timeouts(), read_tcp_data(), read_udp_packets(), time, and write_tcp_data(). Referenced by dns_client(), and gethostbynameaddr(). { time_t now; time(&now); write_tcp_data(channel, write_fds, now); read_tcp_data(channel, read_fds, now); read_udp_packets(channel, read_fds, now); process_timeouts(channel, now); }

Here is the call graph for this function:

void ares_query (  ares_channel  channel, const char *  name, int  dnsclass, int  type, ares_callback  callback, void *  arg )

Definition at line 33 of file ares_query.c. References ares_callback, ares_channel, ARES_ENOMEM, ARES_FLAG_NORECURSE, ares_free_string(), ares_mkquery(), ares_send(), ARES_SUCCESS, callback(), ares_channeldata::flags, malloc, name, ares_channeldata::next_id, NULL, qcallback(), and status. Referenced by ares_search(), next_lookup(), and search_callback(). { struct qquery *qquery; unsigned char *qbuf; int qlen, rd, status; /* Compose the query. */ rd = !(channel->flags & ARES_FLAG_NORECURSE); status = ares_mkquery(name, dnsclass, type, channel->next_id, rd, &qbuf, &qlen); channel->next_id++; if (status != ARES_SUCCESS) { callback(arg, status, NULL, 0); return; } /* Allocate and fill in the query structure. */ qquery = malloc(sizeof(struct qquery)); if (!qquery) { ares_free_string(qbuf); callback(arg, ARES_ENOMEM, NULL, 0); return; } qquery->callback = callback; qquery->arg = arg; /* Send it off. qcallback will be called when we get an answer. */ ares_send(channel, qbuf, qlen, qcallback, qquery); ares_free_string(qbuf); }

Here is the call graph for this function:

void ares_search (  ares_channel  channel, const char *  name, int  dnsclass, int  type, ares_callback  callback, void *  arg )

Definition at line 46 of file ares_search.c. References ares_callback, ares_channel, ARES_ENOMEM, ares_query(), ARES_SUCCESS, callback(), cat_domain(), ares_channeldata::domains, free, malloc, name, ares_channeldata::ndots, NULL, search_callback(), single_domain(), status, and strdup. Referenced by next_lookup(). { struct search_query *squery; char *s; const char *p; int status, ndots; /* If name only yields one domain to search, then we don't have * to keep extra state, so just do an ares_query(). */ status = single_domain(channel, name, &s); if (status != ARES_SUCCESS) { callback(arg, status, NULL, 0); return; } if (s) { ares_query(channel, s, dnsclass, type, callback, arg); free(s); return; } /* Allocate a search_query structure to hold the state necessary for * doing multiple lookups. */ squery = malloc(sizeof(struct search_query)); if (!squery) { callback(arg, ARES_ENOMEM, NULL, 0); return; } squery->channel = channel; squery->name = strdup(name); if(!squery->name) { free(squery); callback(arg, ARES_ENOMEM, NULL, 0); return; } squery->dnsclass = dnsclass; squery->type = type; squery->status_as_is = -1; squery->callback = callback; squery->arg = arg; /* Count the number of dots in name. */ ndots = 0; for (p = name; *p; p++) { if (*p == '.') ndots++; } /* If ndots is at least the channel ndots threshold (usually 1), * then we try the name as-is first. Otherwise, we try the name * as-is last. */ if (ndots >= channel->ndots) { /* Try the name as-is first. */ squery->next_domain = 0; squery->trying_as_is = 1; ares_query(channel, name, dnsclass, type, search_callback, squery); } else { /* Try the name as-is last; start with the first search domain. */ squery->next_domain = 1; squery->trying_as_is = 0; status = cat_domain(name, channel->domains[0], &s); if (status == ARES_SUCCESS) { ares_query(channel, s, dnsclass, type, search_callback, squery); free(s); } else callback(arg, status, NULL, 0); } }

Here is the call graph for this function:

void ares_send (  ares_channel  channel, const unsigned char *  qbuf, int  qlen, ares_callback  callback, void *  arg )

Definition at line 26 of file ares_send.c. References ares__send_query(), ares_callback, ares_channel, ARES_EBADQUERY, ARES_ECONNREFUSED, ARES_ENOMEM, ARES_FLAG_USEVC, callback(), DNS_HEADER_QID, ares_channeldata::flags, free, HFIXEDSZ, malloc, ares_channeldata::nservers, NULL, PACKETSZ, ares_channeldata::queries, and time. Referenced by ares_query(). { struct query *query; int i; time_t now; /* Verify that the query is at least long enough to hold the header. */ if (qlen < HFIXEDSZ #ifndef LWIP || qlen >= (1 << 16) #endif ) { callback(arg, ARES_EBADQUERY, NULL, 0); return; } /* Allocate space for query and allocated fields. */ query = malloc(sizeof(struct query)); if (!query) { callback(arg, ARES_ENOMEM, NULL, 0); return; } query->tcpbuf = malloc(qlen + 2); if (!query->tcpbuf) { free(query); callback(arg, ARES_ENOMEM, NULL, 0); return; } query->skip_server = malloc(channel->nservers * sizeof(int)); if (!query->skip_server) { free(query->tcpbuf); free(query); callback(arg, ARES_ENOMEM, NULL, 0); return; } /* Compute the query ID. Start with no timeout. */ query->qid = DNS_HEADER_QID(qbuf); query->timeout = 0; /* Form the TCP query buffer by prepending qlen (as two * network-order bytes) to qbuf. */ query->tcpbuf[0] = (qlen >> 8) & 0xff; query->tcpbuf[1] = qlen & 0xff; memcpy(query->tcpbuf + 2, qbuf, qlen); query->tcplen = qlen + 2; /* Fill in query arguments. */ query->qbuf = query->tcpbuf + 2; query->qlen = qlen; query->callback = callback; query->arg = arg; /* Initialize query status. */ query->try = 0; query->server = 0; for (i = 0; i < channel->nservers; i++) query->skip_server[i] = 0; query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > PACKETSZ; query->error_status = ARES_ECONNREFUSED; /* Chain the query into this channel's query list. */ query->next = channel->queries; channel->queries = query; /* Perform the first query action. */ time(&now); ares__send_query(channel, query, now); }

Here is the call graph for this function:

const char* ares_strerror (  int  code, char **  memptr )

Definition at line 25 of file ares_strerror.c. Referenced by dns_client(), and dns_client_callback(). { /* A future implementation may want to handle internationalization. * For now, just return a string literal from a table. */ const char *errtext[] = { "Successful completion", "DNS server returned answer with no data", "DNS server claims query was misformatted", "DNS server returned general failure", "Domain name not found", "DNS server does not implement requested operation", "DNS server refused query", "Misformatted DNS query", "Misformatted domain name", "Unsupported address family", "Misformatted DNS reply", "Could not contact DNS servers", "Timeout while contacting DNS servers", "End of file", "Error reading file", "Out of memory" }; (void)memptr; //#ifdef LWIP_ASSERT // LWIP_ASSERT("ares_strerror: code", code >= 0 && code < (sizeof(errtext) / sizeof(*errtext))); //#else // assert(code >= 0 && code < (sizeof(errtext) / sizeof(*errtext))); //#endif return errtext[code]; }

struct timeval* ares_timeout (  ares_channel  channel, struct timeval *  maxtv, struct timeval *  tv )

Definition at line 25 of file ares_timeout.c. References ares_channel, query::next, ares_channeldata::queries, time, timeval::tv_sec, and timeval::tv_usec. Referenced by dns_client(), and gethostbynameaddr(). { struct query *query; time_t now; int offset, min_offset; /* No queries, no timeout (and no fetch of the current time). */ if (!channel->queries) return maxtv; /* Find the minimum timeout for the current set of queries. */ time(&now); min_offset = -1; for (query = channel->queries; query; query = query->next) { if (query->timeout == 0) continue; offset = query->timeout - now; if (offset < 0) offset = 0; if (min_offset == -1 || offset < min_offset) min_offset = offset; } /* If we found a minimum timeout and it's sooner than the one * specified in maxtv (if any), return it. Otherwise go with * maxtv. */ if (min_offset != -1 && (!maxtv || min_offset <= maxtv->tv_sec)) { tvbuf->tv_sec = min_offset; tvbuf->tv_usec = 0; return tvbuf; } else return maxtv; }

---