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Code Activity

udp: restore correct address/port when parsing packet (#6011)

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do interleave informations on addresses within reception pbuf chain:
before: (data-pbuf) -> (data-pbuf) -> (data-pbuf) -> ... in the receiving order
now: (address+port-info-pbuf -> data-pbuf) -> (address_port-info-pbuf -> data-pbuf) -> ...

address/port informations are updated along with data exposed to user
This commit is contained in:
david gauchard
2019-04-26 20:09:23 +02:00
committed by GitHub
parent f6dd826437
commit 5dd780c571
2 changed files with 91 additions and 53 deletions
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24
libraries/ESP8266WiFi/examples/Udp/Udp.ino
View File

@ -26,7 +26,7 @@
unsigned int localPort = 8888; // local port to listen on
// buffers for receiving and sending data
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet,
char packetBuffer[UDP_TX_PACKET_MAX_SIZE + 1]; //buffer to hold incoming packet,
char ReplyBuffer[] = "acknowledged\r\n"; // a string to send back
WiFiUDP Udp;
@ -49,21 +49,15 @@ void loop() {
// if there's data available, read a packet
int packetSize = Udp.parsePacket();
if (packetSize) {
Serial.print("Received packet of size ");
Serial.println(packetSize);
Serial.print("From ");
IPAddress remote = Udp.remoteIP();
for (int i = 0; i < 4; i++) {
Serial.print(remote[i], DEC);
if (i < 3) {
Serial.print(".");
}
}
Serial.print(", port ");
Serial.println(Udp.remotePort());
Serial.printf("Received packet of size %d from %s:%d\n (to %s:%d, free heap = %d B)\n",
packetSize,
Udp.remoteIP().toString().c_str(), Udp.remotePort(),
Udp.destinationIP().toString().c_str(), Udp.localPort(),
ESP.getFreeHeap());
// read the packet into packetBufffer
Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
int n = Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
packetBuffer[n] = 0;
Serial.println("Contents:");
Serial.println(packetBuffer);
@ -72,7 +66,7 @@ void loop() {
Udp.write(ReplyBuffer);
Udp.endPacket();
}
delay(10);
}
/*

120
libraries/ESP8266WiFi/src/include/UdpContext.h
View File

@ -32,7 +32,8 @@ void esp_schedule();
#include <AddrList.h>
#define GET_UDP_HDR(pb) (reinterpret_cast<udp_hdr*>(((uint8_t*)((pb)->payload)) - UDP_HLEN))
#define PBUF_ALIGNER_ADJUST 4
#define PBUF_ALIGNER(x) ((void*)((((intptr_t)(x))+3)&~3))
class UdpContext
{
@ -207,21 +208,17 @@ public:
CONST IPAddress& getRemoteAddress() CONST
{
return _src_addr;
return _currentAddr.srcaddr;
}
uint16_t getRemotePort() const
{
if (!_rx_buf)
return 0;
udp_hdr* udphdr = GET_UDP_HDR(_rx_buf);
return lwip_ntohs(udphdr->src);
return _currentAddr.srcport;
}
const IPAddress& getDestAddress() const
{
return _dst_addr;
return _currentAddr.dstaddr;
}
uint16_t getLocalPort() const
@ -235,23 +232,41 @@ public:
{
if (!_rx_buf)
return false;
if (!_first_buf_taken)
{
_first_buf_taken = true;
return true;
}
auto head = _rx_buf;
auto deleteme = _rx_buf;
_rx_buf = _rx_buf->next;
_rx_buf_offset = 0;
if (_rx_buf)
{
// we have interleaved informations on addresses within reception pbuf chain:
// before: (data-pbuf) -> (data-pbuf) -> (data-pbuf) -> ... in the receiving order
// now: (address-info-pbuf -> data-pbuf) -> (address-info-pbuf -> data-pbuf) -> ...
// so the first rx_buf contains an address helper,
// copy it to "current address"
auto helper = (AddrHelper*)PBUF_ALIGNER(_rx_buf->payload);
_currentAddr = *helper;
// destroy the helper in the about-to-be-released pbuf
helper->~AddrHelper();
// forward in rx_buf list, next one is effective data
// current (not ref'ed) one will be pbuf_free'd with deleteme
_rx_buf = _rx_buf->next;
// this rx_buf is not nullptr by construction,
// ref'ing it to prevent release from the below pbuf_free(deleteme)
pbuf_ref(_rx_buf);
}
pbuf_free(head);
return _rx_buf != 0;
pbuf_free(deleteme);
_rx_buf_offset = 0;
return _rx_buf != nullptr;
}
int read()
@ -420,54 +435,74 @@ private:
}
void _recv(udp_pcb *upcb, pbuf *pb,
const ip_addr_t *addr, u16_t port)
const ip_addr_t *srcaddr, u16_t srcport)
{
(void) upcb;
(void) addr;
(void) port;
#if LWIP_VERSION_MAJOR == 1
#define TEMPDSTADDR (&current_iphdr_dest)
#else
#define TEMPDSTADDR (ip_current_dest_addr())
#endif
// chain this helper pbuf first
if (_rx_buf)
{
// there is some unread data
// chain the new pbuf to the existing one
// chain pbuf
// Addresses/ports are stored from this callback because lwIP's
// macro are valid only now.
//
// When peeking data from before payload start (like it was done
// before IPv6), there's no easy way to safely guess whether
// packet is from v4 or v6.
//
// Now storing data in an intermediate chained pbuf containing
// AddrHelper
// allocate new pbuf to store addresses/ports
pbuf* pb_helper = pbuf_alloc(PBUF_RAW, sizeof(AddrHelper) + PBUF_ALIGNER_ADJUST, PBUF_RAM);
if (!pb_helper)
{
// memory issue - discard received data
pbuf_free(pb);
return;
}
// construct in place
new(PBUF_ALIGNER(pb_helper->payload)) AddrHelper(srcaddr, TEMPDSTADDR, srcport);
// chain it
pbuf_cat(_rx_buf, pb_helper);
// now chain the new data pbuf
DEBUGV(":urch %d, %d\r\n", _rx_buf->tot_len, pb->tot_len);
pbuf_cat(_rx_buf, pb);
}
else
{
_currentAddr.srcaddr = srcaddr;
_currentAddr.dstaddr = TEMPDSTADDR;
_currentAddr.srcport = srcport;
DEBUGV(":urn %d\r\n", pb->tot_len);
_first_buf_taken = false;
_rx_buf = pb;
_rx_buf_offset = 0;
}
// --> Arduino's UDP is a stream but UDP is not <--
// When IPv6 is enabled, we store addresses from here
// because lwIP's macro are valid only in this callback
// (there's no easy way to safely guess whether packet
// is from v4 or v6 when we have only access to payload)
// Because of this stream-ed way this is inacurate when
// user does not swallow data quickly enough (the former
// IPv4-only way suffers from the exact same issue.
#if LWIP_VERSION_MAJOR == 1
_src_addr = current_iphdr_src;
_dst_addr = current_iphdr_dest;
#else
_src_addr = ip_data.current_iphdr_src;
_dst_addr = ip_data.current_iphdr_dest;
#endif
if (_on_rx) {
_on_rx();
}
}
#undef TEMPDSTADDR
}
static void _s_recv(void *arg,
udp_pcb *upcb, pbuf *p,
CONST ip_addr_t *addr, u16_t port)
CONST ip_addr_t *srcaddr, u16_t srcport)
{
reinterpret_cast<UdpContext*>(arg)->_recv(upcb, p, addr, port);
reinterpret_cast<UdpContext*>(arg)->_recv(upcb, p, srcaddr, srcport);
}
private:
@ -483,7 +518,16 @@ private:
#ifdef LWIP_MAYBE_XCC
uint16_t _mcast_ttl;
#endif
IPAddress _src_addr, _dst_addr;
struct AddrHelper
{
IPAddress srcaddr, dstaddr;
int16_t srcport;
AddrHelper() { }
AddrHelper(const ip_addr_t* src, const ip_addr_t* dst, uint16_t srcport):
srcaddr(src), dstaddr(dst), srcport(srcport) { }
};
AddrHelper _currentAddr;
};