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dns-sd: avahi: Code cleanup
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- Fix misplaced \n in debug print
- Simplify new_discovery_data()
- List one function parameter per line, as these functions take a lot of
  arguments
- Remove __notused, since we always compile with -Wno-unused-parameter
- Avoid a(b(c(d))), this is C, not Lisp
- Replace "i = 0; while(xxx) { ... ; i++ }" with a for loop
- Put arguments of long log messages to a new line
- Properly align code with tabs and complete with chars

Signed-off-by: Paul Cercueil <[email protected]>
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@pcercuei
pcercuei committed May 11, 2021
1 parent b391071 commit 5fd8fce
Showing 1 changed file with 122 additions and 94 deletions.
216 changes: 122 additions & 94 deletions dns_sd_avahi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,54 +33,57 @@
* potential clients on the network
*/

static int new_discovery_data(struct dns_sd_discovery_data **data)
static struct dns_sd_discovery_data *new_discovery_data(void)
{
struct dns_sd_discovery_data *d;

d = zalloc(sizeof(struct dns_sd_discovery_data));
d = zalloc(sizeof(*d));
if (!d)
return -ENOMEM;
return NULL;

d->address = zalloc(sizeof(struct AvahiAddress));
d->address = zalloc(sizeof(*d->address));
if (!d->address) {
free(d);
return -ENOMEM;
return NULL;
}

*data = d;
return 0;
return d;
}

static void avahi_process_resolved(struct dns_sd_discovery_data *ddata, const AvahiAddress *addr,
const char *host_name, const uint16_t port)
static void avahi_process_resolved(struct dns_sd_discovery_data *ddata,
const AvahiAddress *addr,
const char *host_name,
const uint16_t port)
{
/* Avahi is multi-threaded, so lock the list */
iio_mutex_lock(ddata->lock);
ddata->resolved++;

/* Find empty data to store things*/
while (ddata->next)
ddata = ddata->next;

/* link a new placeholder to the list */
avahi_address_snprint(ddata->addr_str,
sizeof(ddata->addr_str), addr);
memcpy(ddata->address, addr, sizeof(*ddata->address)); /* Flawfinder: ignore */
ddata->port = port;
ddata->hostname = strdup(host_name);
ddata->resolved = true;
/* link a new, empty placeholder to the list */
if (!new_discovery_data(&ddata->next)) {
/* duplicate poll & lock info,
* since we don't know which might be discarded */
ddata->next->poll = ddata->poll;
ddata->next->lock = ddata->lock;
} else {
IIO_ERROR("Avahi Resolver : memory failure\n");
}
iio_mutex_unlock(ddata->lock);

IIO_DEBUG("\t\t%s:%u (%s)\n", host_name, port, ddata->addr_str);
/* Avahi is multi-threaded, so lock the list */
iio_mutex_lock(ddata->lock);
ddata->resolved++;

/* Find empty data to store things*/
while (ddata->next)
ddata = ddata->next;

/* link a new placeholder to the list */
avahi_address_snprint(ddata->addr_str,
sizeof(ddata->addr_str), addr);
memcpy(ddata->address, addr, sizeof(*ddata->address)); /* Flawfinder: ignore */
ddata->port = port;
ddata->hostname = strdup(host_name);
ddata->resolved = true;

/* link a new, empty placeholder to the list */
ddata->next = new_discovery_data();
if (ddata->next) {
/* duplicate poll & lock info,
* since we don't know which might be discarded */
ddata->next->poll = ddata->poll;
ddata->next->lock = ddata->lock;
} else {
IIO_ERROR("Avahi Resolver : memory failure\n");
}
iio_mutex_unlock(ddata->lock);

IIO_DEBUG("\t\t%s:%u (%s)\n", host_name, port, ddata->addr_str);
}

/*
Expand All @@ -90,14 +93,22 @@ static void avahi_process_resolved(struct dns_sd_discovery_data *ddata, const Av
*/

static void __avahi_resolver_cb(AvahiServiceResolver *resolver,
__notused AvahiIfIndex iface, __notused AvahiProtocol proto,
AvahiResolverEvent event, const char *name,
const char *type, const char *domain,
const char *host_name, const AvahiAddress *address,
uint16_t port, AvahiStringList *txt,
__notused AvahiLookupResultFlags flags, void *d)
AvahiIfIndex iface,
AvahiProtocol proto,
AvahiResolverEvent event,
const char *name,
const char *type,
const char *domain,
const char *host_name,
const AvahiAddress *address,
uint16_t port,
AvahiStringList *txt,
AvahiLookupResultFlags flags,
void *d)
{
struct dns_sd_discovery_data *ddata = (struct dns_sd_discovery_data *) d;
struct dns_sd_discovery_data *ddata = d;
AvahiClient *client;
int err;

if (!resolver) {
IIO_ERROR("Fatal Error in Avahi Resolver\n");
Expand All @@ -106,36 +117,44 @@ static void __avahi_resolver_cb(AvahiServiceResolver *resolver,

switch(event) {
case AVAHI_RESOLVER_FAILURE:
client = avahi_service_resolver_get_client(resolver);
err = avahi_client_errno(client);

IIO_ERROR("Avahi Resolver: Failed resolve service '%s' "
"of type '%s' in domain '%s': %s\n",
name, type, domain,
avahi_strerror(
avahi_client_errno(
avahi_service_resolver_get_client(
resolver))));
"of type '%s' in domain '%s': %s\n",
name, type, domain,
avahi_strerror(err));
break;
case AVAHI_RESOLVER_FOUND: {
avahi_process_resolved(ddata, address, host_name, port);
IIO_DEBUG("Avahi Resolver : service '%s' of type '%s' in domain '%s':\n",
name, type, domain);
name, type, domain);
break;
}
}
}
avahi_service_resolver_free(resolver);
}

static void avahi_host_resolver(AvahiHostNameResolver *resolver, __notused AvahiIfIndex iface,
__notused AvahiProtocol proto, AvahiResolverEvent event,
const char *host_name, const AvahiAddress *address,
__notused AvahiLookupResultFlags flags, void *d)
static void avahi_host_resolver(AvahiHostNameResolver *resolver,
AvahiIfIndex iface,
AvahiProtocol proto,
AvahiResolverEvent event,
const char *host_name,
const AvahiAddress *address,
AvahiLookupResultFlags flags,
void *d)
{
struct dns_sd_discovery_data *ddata = (struct dns_sd_discovery_data *) d;
struct dns_sd_discovery_data *ddata = d;
AvahiClient *client;
int err;

switch(event) {
case AVAHI_RESOLVER_FAILURE:
IIO_ERROR("Avahi Resolver: Failed to resolve host '%s' : %s\n", host_name,
avahi_strerror(avahi_client_errno(
avahi_host_name_resolver_get_client(resolver))));
client = avahi_host_name_resolver_get_client(resolver);
err = avahi_client_errno(client);

IIO_ERROR("Avahi Resolver: Failed to resolve host '%s' : %s\n",
host_name, avahi_strerror(err));
break;
case AVAHI_RESOLVER_FOUND:
avahi_process_resolved(ddata, address, host_name, IIOD_PORT);
Expand All @@ -147,14 +166,22 @@ static void avahi_host_resolver(AvahiHostNameResolver *resolver, __notused Avahi
}

static void __avahi_browser_cb(AvahiServiceBrowser *browser,
AvahiIfIndex iface, AvahiProtocol proto,
AvahiBrowserEvent event, const char *name,
const char *type, const char *domain,
__notused AvahiLookupResultFlags flags, void *d)
AvahiIfIndex iface,
AvahiProtocol proto,
AvahiBrowserEvent event,
const char *name,
const char *type,
const char *domain,
AvahiLookupResultFlags flags,
void *d)
{
struct dns_sd_discovery_data *ddata = (struct dns_sd_discovery_data *) d;
struct AvahiClient *client = avahi_service_browser_get_client(browser);
int i;
unsigned int i;
struct timespec ts;

ts.tv_sec = 0;
ts.tv_nsec = 5e6; /* 5ms in ns */

if (!browser) {
IIO_ERROR("Fatal Error in Avahi Browser\n");
Expand All @@ -163,18 +190,16 @@ static void __avahi_browser_cb(AvahiServiceBrowser *browser,

switch (event) {
case AVAHI_BROWSER_REMOVE:
IIO_DEBUG("Avahi Browser : REMOVE : "
"service '%s' of type '%s' in domain '%s'\n",
name, type, domain);
IIO_DEBUG("Avahi Browser : REMOVE : service '%s' of type '%s' in domain '%s'\n",
name, type, domain);
break;
case AVAHI_BROWSER_NEW:
IIO_DEBUG("Avahi Browser : NEW: "
"service '%s' of type '%s' in domain '%s'\n",
name, type, domain);
IIO_DEBUG("Avahi Browser : NEW: service '%s' of type '%s' in domain '%s'\n",
name, type, domain);
if(!avahi_service_resolver_new(client, iface,
proto, name, type, domain,
AVAHI_PROTO_UNSPEC, 0,
__avahi_resolver_cb, d)) {
proto, name, type, domain,
AVAHI_PROTO_UNSPEC, 0,
__avahi_resolver_cb, d)) {
IIO_ERROR("Failed to resolve service '%s\n", name);
} else {
iio_mutex_lock(ddata->lock);
Expand All @@ -183,18 +208,13 @@ static void __avahi_browser_cb(AvahiServiceBrowser *browser,
}
break;
case AVAHI_BROWSER_ALL_FOR_NOW:
/* Wait for a max of 1 second */
i = 0;
IIO_DEBUG("Avahi Browser : ALL_FOR_NOW Browser : %d, Resolved : %d\n",
ddata->found, ddata->resolved);
ddata->found, ddata->resolved);

/* 200 * 5ms = wait 1 second */
while ((ddata->found != ddata->resolved) && i <= 200) {
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 5e6; /* 5ms in ns*/
for (i = 0; ddata->found != ddata->resolved && i <= 200; i++)
nanosleep(&ts, NULL);
i++;
}

avahi_simple_poll_quit(ddata->poll);
break;
case AVAHI_BROWSER_FAILURE:
Expand All @@ -220,7 +240,8 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
AvahiServiceBrowser *browser;
int ret = 0;

if (new_discovery_data(&d) < 0)
d = new_discovery_data();
if (!d)
return -ENOMEM;

d->lock = iio_mutex_create();
Expand All @@ -237,20 +258,21 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
}

client = avahi_client_new(avahi_simple_poll_get(d->poll),
0, NULL, NULL, &ret);
0, NULL, NULL, &ret);
if (!client) {
IIO_ERROR("Unable to create Avahi DNS-SD client :%s\n",
avahi_strerror(ret));
avahi_strerror(ret));
goto err_free_poll;
}

browser = avahi_service_browser_new(client,
AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC,
"_iio._tcp", NULL, 0, __avahi_browser_cb, d);
AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC,
"_iio._tcp", NULL, 0,
__avahi_browser_cb, d);
if (!browser) {
ret = avahi_client_errno(client);
IIO_ERROR("Unable to create Avahi DNS-SD browser: %s\n",
avahi_strerror(ret));
avahi_strerror(ret));
goto err_free_client;
}

Expand All @@ -274,7 +296,8 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
return ret;
}

static void avahi_resolve_host(struct dns_sd_discovery_data *d, const char *hostname,
static void avahi_resolve_host(struct dns_sd_discovery_data *d,
const char *hostname,
const AvahiProtocol proto)
{
AvahiClient *client;
Expand All @@ -287,19 +310,21 @@ static void avahi_resolve_host(struct dns_sd_discovery_data *d, const char *host

client = avahi_client_new(avahi_simple_poll_get(d->poll), 0, NULL, NULL, &ret);
if (!client) {
IIO_ERROR("Unable to create Avahi DNS-SD client :%s\n", avahi_strerror(ret));
IIO_ERROR("Unable to create Avahi DNS-SD client :%s\n",
avahi_strerror(ret));
goto err_free_poll;
}

resolver = avahi_host_name_resolver_new(client, AVAHI_IF_UNSPEC, proto, hostname, proto, 0,
avahi_host_resolver, d);
if (!resolver) {
ret = avahi_client_errno(client);
IIO_ERROR("Unable to create Avahi DNS-SD browser: %s\n", avahi_strerror(ret));
IIO_ERROR("Unable to create Avahi DNS-SD browser: %s\n",
avahi_strerror(ret));
goto err_free_client;
}

IIO_DEBUG("Trying to resolve host: %s\n, proto: %d", hostname, proto);
IIO_DEBUG("Trying to resolve host: %s, proto: %d\n", hostname, proto);
avahi_simple_poll_loop(d->poll);

err_free_client:
Expand All @@ -308,15 +333,18 @@ static void avahi_resolve_host(struct dns_sd_discovery_data *d, const char *host
avahi_simple_poll_free(d->poll);
}

int dnssd_resolve_host(const char *hostname, char *ip_addr, const int addr_len)
int dnssd_resolve_host(const char *hostname,
char *ip_addr,
const int addr_len)
{
struct dns_sd_discovery_data *d;
int ret = 0;

if (!hostname || hostname[0] == '\0')
return -EINVAL;

if (new_discovery_data(&d) < 0)
d = new_discovery_data();
if (!d)
return -ENOMEM;

d->lock = iio_mutex_create();
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