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Apply patch #9523: MDNS responder should reply after a random timeout

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with a few cleanups and coding style fixes
This commit is contained in:
Dirk Ziegelmeier 2018-01-02 22:20:25 +01:00
parent 004b13ca09
commit fa345b0f22
1 changed files with 77 additions and 13 deletions
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90
src/apps/mdns/mdns.c
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@ -61,6 +61,7 @@
#include "lwip/udp.h"
#include "lwip/ip_addr.h"
#include "lwip/mem.h"
#include "lwip/timeouts.h"
#include "lwip/prot/dns.h"
#include "lwip/prot/iana.h"
@ -243,6 +244,18 @@ struct mdns_rr_info {
u16_t klass;
};
/** Information about outgoing packet */
struct mdns_async_outpacket {
/** Netif to send the packet on */
struct netif *netif;
/** Packet data */
struct pbuf *pbuf;
/** Destination IP */
ip_addr_t dest_addr;
/** Destination port */
u16_t dest_port;
};
struct mdns_question {
struct mdns_rr_info info;
/** unicast reply requested */
@ -1255,7 +1268,7 @@ mdns_init_outpacket(struct mdns_outpacket *out, struct mdns_packet *in)
/* Copy source IP/port to use when responding unicast, or to choose
* which pcb to use for multicast (IPv4/IPv6)
*/
SMEMCPY(&out->dest_addr, &in->source_addr, sizeof(ip_addr_t));
ip_addr_copy(out->dest_addr, in->source_addr);
out->dest_port = in->source_port;
if (in->source_port != LWIP_IANA_PORT_MDNS) {
@ -1272,6 +1285,33 @@ mdns_init_outpacket(struct mdns_outpacket *out, struct mdns_packet *in)
}
}
/**
* Send delayed response
* @param arg An allocated mdns_async_outpacket structure
*/
static void
mdns_async_send_outpacket(void *arg)
{
const ip_addr_t *mcast_destaddr;
struct mdns_async_outpacket *outpkt = (struct mdns_async_outpacket *)arg;
struct pbuf *p = outpkt->pbuf;
/* Send delayed packet */
LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Async sending packet len=%"U16_F"\n", p->tot_len));
if (IP_IS_V6_VAL(outpkt->dest_addr)) {
#if LWIP_IPV6
mcast_destaddr = &v6group;
#endif
} else {
#if LWIP_IPV4
mcast_destaddr = &v4group;
#endif
}
udp_sendto_if(mdns_pcb, p, &outpkt->dest_addr, outpkt->dest_port, outpkt->netif);
pbuf_free(p);
outpkt->pbuf = NULL;
mem_free(arg);
}
/**
* Send chosen answers as a reply
*
@ -1434,7 +1474,6 @@ mdns_send_outpacket(struct mdns_outpacket *outpkt)
}
if (outpkt->pbuf) {
const ip_addr_t *mcast_destaddr;
struct dns_hdr hdr;
/* Write header */
@ -1451,21 +1490,46 @@ mdns_send_outpacket(struct mdns_outpacket *outpkt)
/* Shrink packet */
pbuf_realloc(outpkt->pbuf, outpkt->write_offset);
if (IP_IS_V6_VAL(outpkt->dest_addr)) {
if (outpkt->unicast_reply == 0) {
outpkt->dest_port = LWIP_IANA_PORT_MDNS;
if (IP_IS_V6_VAL(outpkt->dest_addr)) {
#if LWIP_IPV6
mcast_destaddr = &v6group;
ip_addr_copy(outpkt->dest_addr, v6group);
#endif
} else {
} else {
#if LWIP_IPV4
mcast_destaddr = &v4group;
ip_addr_copy(outpkt->dest_addr, v4group);
#endif
}
}
/* Send created packet */
LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Sending packet, len=%d, unicast=%d\n", outpkt->write_offset, outpkt->unicast_reply));
if (outpkt->unicast_reply) {
udp_sendto_if(mdns_pcb, outpkt->pbuf, &outpkt->dest_addr, outpkt->dest_port, outpkt->netif);
/* Delayed answer? See 6.3 in RFC 6762. */
if (outpkt->answers > 1) {
struct mdns_async_outpacket *async_outpkt;
async_outpkt = mem_malloc(sizeof(struct mdns_async_outpacket));
if (async_outpkt) {
struct pbuf *p = outpkt->pbuf;
u32_t msecs = 0;
while (msecs < 20) {
msecs = LWIP_RAND() & 127;
}
outpkt->pbuf = NULL;
async_outpkt->pbuf = p;
async_outpkt->netif = outpkt->netif;
async_outpkt->dest_port = outpkt->dest_port;
ip_addr_copy(async_outpkt->dest_addr, outpkt->dest_addr);
LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Wait sending packet wait=%"U32_F", len=%"U16_F"\n", msecs, p->tot_len));
sys_timeout(msecs, mdns_async_send_outpacket, async_outpkt);
}
} else {
udp_sendto_if(mdns_pcb, outpkt->pbuf, mcast_destaddr, LWIP_IANA_PORT_MDNS, outpkt->netif);
/* Immediately send created packet */
LWIP_DEBUGF(MDNS_DEBUG, ("MDNS: Sending packet, len=%"U16_F", unicast=%"U16_F"\n", outpkt->write_offset, outpkt->unicast_reply));
udp_sendto_if(mdns_pcb, outpkt->pbuf, &outpkt->dest_addr, outpkt->dest_port, outpkt->netif);
}
}
@ -1514,7 +1578,7 @@ mdns_announce(struct netif *netif, const ip_addr_t *destination)
}
announce.dest_port = LWIP_IANA_PORT_MDNS;
SMEMCPY(&announce.dest_addr, destination, sizeof(announce.dest_addr));
ip_addr_copy(announce.dest_addr, *destination);
mdns_send_outpacket(&announce);
}
@ -1803,7 +1867,7 @@ mdns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr,
}
memset(&packet, 0, sizeof(packet));
SMEMCPY(&packet.source_addr, addr, sizeof(packet.source_addr));
ip_addr_copy(packet.source_addr, *addr);
packet.source_port = port;
packet.netif = recv_netif;
packet.pbuf = p;