Commit dbe0c6f6 authored by Nick Mathewson's avatar Nick Mathewson 🏃
Browse files

r8609@Kushana: nickm | 2006-08-27 17:24:27 -0400

 Add some doxygen, concentrated in dns.c


svn:r8256
parent 54ca0387
......@@ -58,11 +58,15 @@ struct buf_t {
char *cur; /**< The first byte used for storing data in the buffer. */
size_t highwater; /**< Largest observed datalen since last buf_shrink */
size_t len; /**< Maximum amount of data that <b>mem</b> can hold. */
size_t memsize; /**< DOCDOC */
size_t memsize; /**< How many bytes did we actually allocate? Can be less
* than 'len' if we shortened 'len' by a few bytes to make
* zlib wrap around more easily. */
size_t datalen; /**< Number of bytes currently in <b>mem</b>. */
};
/** How many bytes, total, are used in all buffers? */
uint64_t buf_total_used = 0;
/** How many bytes, total, are allocated in all buffers? */
uint64_t buf_total_alloc = 0;
/** Size, in bytes, for newly allocated buffers. Should be a power of 2. */
......@@ -1292,7 +1296,10 @@ fetch_from_buf_line(buf_t *buf, char *data_out, size_t *data_len)
return 1;
}
/** DOCDOC */
/** Compress on uncompress the <b>data_len</b> bytes in <b>data</b> using the
* zlib state <b>state</b>, appending the result to <b>buf</b>. If
* <b>done</b> is true, flush the data in the state and finish the
* compression/uncompression. Return -1 on failure, 0 on success. */
int
write_to_buf_zlib(buf_t *buf, tor_zlib_state_t *state,
const char *data, size_t data_len,
......
......@@ -51,6 +51,15 @@ static int num_dnsworkers=0;
static int num_dnsworkers_busy=0;
/** When did we last rotate the dnsworkers? */
static time_t last_rotation_time=0;
#else
/** Have we currently configured nameservers with eventdns? */
static int nameservers_configured = 0;
/** What was the resolv_conf fname we last used when configuring the
* nameservers? Used to check whether we need to reconfigure. */
static char *resolv_conf_fname = NULL;
/** What was the mtime on the resolv.conf file we last used when configuring
* the nameservers? Used to check whether we need to reconfigure. */
static time_t resolv_conf_mtime = 0;
#endif
/** Linked list of connections waiting for a DNS answer. */
......@@ -92,6 +101,7 @@ typedef struct cached_resolve_t {
uint8_t state; /**< Is this cached entry pending/done/valid/failed? */
time_t expire; /**< Remove items from cache after this time. */
uint32_t ttl; /**< What TTL did the nameserver tell us? */
/** Connections that want to know when we get an answer for this resolve. */
pending_connection_t *pending_connections;
} cached_resolve_t;
......@@ -116,13 +126,6 @@ static void _assert_cache_ok(void);
#endif
static void assert_resolve_ok(cached_resolve_t *resolve);
#ifdef USE_EVENTDNS
/* DOCDOC */
static int nameservers_configured = 0;
static char *resolv_conf_fname = NULL;
static time_t resolv_conf_mtime = 0;
#endif
/** Hash table of cached_resolve objects. */
static HT_HEAD(cache_map, cached_resolve_t) cache_root;
......@@ -136,6 +139,7 @@ cached_resolves_eq(cached_resolve_t *a, cached_resolve_t *b)
return !strncmp(a->address, b->address, MAX_ADDRESSLEN);
}
/** Hash function for cached_resolve objects */
static INLINE unsigned int
cached_resolve_hash(cached_resolve_t *a)
{
......@@ -155,6 +159,7 @@ init_cache_map(void)
}
#ifdef USE_EVENTDNS
/** Helper: called by eventdns when eventdns wants to log something. */
static void
eventdns_log_cb(int warn, const char *msg)
{
......@@ -162,6 +167,8 @@ eventdns_log_cb(int warn, const char *msg)
get_options()->SafeLogging) {
log(LOG_INFO, LD_EXIT, "eventdns: Resolve requested.");
return;
} else if (!strcmpstart(msg, "Search: ")) {
return;
}
log(warn?LOG_WARN:LOG_INFO, LD_EXIT, "eventdns: %s", msg);
}
......@@ -181,7 +188,7 @@ dns_init(void)
return 0;
}
/* DOCDOC */
/** Called when DNS-related options change (or may have changed) */
void
dns_reset(void)
{
......@@ -203,6 +210,8 @@ dns_reset(void)
#endif
}
/** Helper: Given a TTL from a DNS response, determine what TTL to give the
* OP that asked us to resolve it. */
uint32_t
dns_clip_ttl(uint32_t ttl)
{
......@@ -214,6 +223,8 @@ dns_clip_ttl(uint32_t ttl)
return ttl;
}
/** Helper: Given a TTL from a DNS response, determine how long to hold it in
* our cache. */
static uint32_t
dns_get_expiry_ttl(uint32_t ttl)
{
......@@ -266,7 +277,7 @@ set_expiry(cached_resolve_t *resolve, time_t expires)
resolve);
}
/** Free all storage held in the DNS cache */
/** Free all storage held in the DNS cache and related structures. */
void
dns_free_all(void)
{
......@@ -280,6 +291,9 @@ dns_free_all(void)
if (cached_resolve_pqueue)
smartlist_free(cached_resolve_pqueue);
cached_resolve_pqueue = NULL;
#ifdef USE_EVENTDNS
tor_free(resolv_conf_fname);
#endif
}
/** Remove every cached_resolve whose <b>expire</b> time is before <b>now</b>
......@@ -660,6 +674,9 @@ dns_cancel_pending_resolve(char *address)
tor_free(resolve);
}
/** Helper: adds an entry to the DNS cache mapping <b>address</b> to the ipv4
* address 'addr'. 'ttl is a cache ttl; 'outcome' is one of
* DNS_RESOLVE_{FAILED_TRANSIENT|FAILED_PERMANENT|SUCCEEDED}. */
static void
add_answer_to_cache(const char *address, uint32_t addr, char outcome,
uint32_t ttl)
......@@ -680,11 +697,11 @@ add_answer_to_cache(const char *address, uint32_t addr, char outcome,
set_expiry(resolve, time(NULL) + dns_get_expiry_ttl(ttl));
}
/** Called on the OR side when a DNS worker tells us the outcome of a DNS
* resolve: tell all pending connections about the result of the lookup, and
* cache the value. (<b>address</b> is a NUL-terminated string containing the
* address to look up; <b>addr</b> is an IPv4 address in host order;
* <b>outcome</b> is one of
/** Called on the OR side when a DNS worker or the eventdns library tells us
* the outcome of a DNS resolve: tell all pending connections about the result
* of the lookup, and cache the value. (<b>address</b> is a NUL-terminated
* string containing the address to look up; <b>addr</b> is an IPv4 address in
* host order; <b>outcome</b> is one of
* DNS_RESOLVE_{FAILED_TRANSIENT|FAILED_PERMANENT|SUCCEEDED}.
*/
static void
......@@ -862,6 +879,8 @@ connection_dns_finished_flushing(connection_t *conn)
return 0;
}
/** Called when a connection to a dnsworker hits an EOF; this only happens
* when a dnsworker dies unexpectedly. */
int
connection_dns_reached_eof(connection_t *conn)
{
......@@ -1180,6 +1199,9 @@ spawn_enough_dnsworkers(void)
return 0;
}
#else /* !USE_EVENTDNS */
/** Eventdns helper: return true iff the eventdns result <b>err</b> is
* a transient failure. */
static int
eventdns_err_is_transient(int err)
{
......@@ -1193,6 +1215,7 @@ eventdns_err_is_transient(int err)
return 0;
}
}
/* Dummy function; never called with eventdns enabled. */
int
connection_dns_finished_flushing(connection_t *conn)
{
......@@ -1200,6 +1223,7 @@ connection_dns_finished_flushing(connection_t *conn)
tor_assert(0);
return 0;
}
/* Dummy function; never called with eventdns enabled. */
int
connection_dns_process_inbuf(connection_t *conn)
{
......@@ -1207,6 +1231,7 @@ connection_dns_process_inbuf(connection_t *conn)
tor_assert(0);
return 0;
}
/* Dummy function; never called with eventdns enabled. */
int
connection_dns_reached_eof(connection_t *conn)
{
......@@ -1215,7 +1240,11 @@ connection_dns_reached_eof(connection_t *conn)
return 0;
}
/* DOCDOC */
/** Configure eventdns nameservers if force is true, or if the configuration
* has changed since the last time we called this function. On Unix, this
* reads from options->ResolvConf or /etc/resolv.conf; on Windows, this reads
* from options->ResolvConf or the registry. Return 0 on success or -1 on
* failure. */
static int
configure_nameservers(int force)
{
......@@ -1283,7 +1312,9 @@ configure_nameservers(int force)
return 0;
}
/* XXX DOCDOC */
/** For eventdns: Called when we get an answer for a request we launched.
* See eventdns.h for arguments; 'arg' holds the address we tried to resolve.
*/
static void
eventdns_callback(int result, char type, int count, int ttl, void *addresses,
void *arg)
......@@ -1318,16 +1349,21 @@ eventdns_callback(int result, char type, int count, int ttl, void *addresses,
tor_free(string_address);
}
/* XXX DOCDOC */
/** For eventdns: start resolving as necessary to find the target for
* <b>exitconn</b> */
static int
launch_resolve(edge_connection_t *exitconn)
{
char *addr = tor_strdup(exitconn->_base.address);
int r;
int options = get_options()->SearchDomains ? 0 : DNS_QUERY_NO_SEARCH;
if (!nameservers_configured)
/* What? Nameservers not configured? Sounds like a bug. */
if (!nameservers_configured) {
log_warn(LD_EXIT, "Harmless bug: nameservers not configured, but resolve "
"launched. Configuring.");
if (configure_nameservers(1) < 0)
return -1;
}
log_info(LD_EXIT, "Launching eventdns request for %s",
escaped_safe_str(exitconn->_base.address));
r = eventdns_resolve_ipv4(exitconn->_base.address, options,
......@@ -1350,6 +1386,7 @@ launch_resolve(edge_connection_t *exitconn)
}
#endif /* USE_EVENTDNS */
/** Exit with an assertion if <b>resolve</b> is corrupt. */
static void
assert_resolve_ok(cached_resolve_t *resolve)
{
......@@ -1368,6 +1405,7 @@ assert_resolve_ok(cached_resolve_t *resolve)
}
#ifdef DEBUG_DNS_CACHE
/** Exit with an assertion if the DNS cache is corrupt. */
static void
_assert_cache_ok(void)
{
......
......@@ -1579,7 +1579,7 @@ int eventdns_resolve_reverse(struct in_addr *in, int flags, eventdns_callback_ty
(int)(u8)((a>>8 )&0xff),
(int)(u8)((a>>16)&0xff),
(int)(u8)((a>>24)&0xff));
log(0, "reverse resolve requested for %s", buf);
log(0, "Resolve requested for %s (reverse)", buf);
req = request_new(TYPE_PTR, buf, flags, callback, ptr);
if (!req) return 1;
request_submit(req);
......
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