Tom Soulanille / snet

simple reliable networking over ethernet. Provides IPv4 ARP, ICMP echo reply, and UDP unicast. Does NOT provide TCP, that's not simple :-).

snet.cpp@1:9c211ac06a12, 2015-03-05 (annotated)

Committer:
altasoul
Date:
Thu Mar 05 00:18:25 2015 +0000
Revision:
1:9c211ac06a12
Parent:
0:6df0a6ed91d4
Child:
2:397316d97354
refactor Snet to have registered_udp_handler

Who changed what in which revision?

UserRevisionLine numberNew contents of line
altasoul 0:6df0a6ed91d4 1 #include "snet.h"
altasoul 0:6df0a6ed91d4 2
altasoul 0:6df0a6ed91d4 3 //extern MODSERIAL pc;
altasoul 0:6df0a6ed91d4 4
altasoul 0:6df0a6ed91d4 5 //extern void print_hex(uint8_t *p, int len);
altasoul 0:6df0a6ed91d4 6
altasoul 0:6df0a6ed91d4 7 //volatile uint32_t enet_rx_cnt;
altasoul 0:6df0a6ed91d4 8 //volatile int enet_rx_balance;
altasoul 0:6df0a6ed91d4 9
altasoul 0:6df0a6ed91d4 10 const uint8_t Snet::broadcast_mac[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
altasoul 0:6df0a6ed91d4 11 const uint8_t Snet::ipEtherType[] = { 0x08, 0x00 };
altasoul 0:6df0a6ed91d4 12 const uint8_t Snet::arp_req_payload_prefix[] = { 0x0, 0x1, 0x8, 0x0, 0x6, 0x4, 0x0, 0x1 };
altasoul 0:6df0a6ed91d4 13
altasoul 0:6df0a6ed91d4 14
altasoul 0:6df0a6ed91d4 15 Snet::Snet(): eth()
altasoul 0:6df0a6ed91d4 16 {
altasoul 0:6df0a6ed91d4 17 eth.address((char *) my_mac);
altasoul 0:6df0a6ed91d4 18 printf("MAC %02x:%02x:%02x:%02x:%02x:%02x\r\n",
altasoul 0:6df0a6ed91d4 19 my_mac[0], my_mac[1], my_mac[2], my_mac[3], my_mac[4], my_mac[5]);
altasoul 0:6df0a6ed91d4 20 printf("no IP\r\n");
altasoul 0:6df0a6ed91d4 21 }
altasoul 0:6df0a6ed91d4 22
altasoul 0:6df0a6ed91d4 23 Snet::Snet(const uint8_t *ip): eth()
altasoul 0:6df0a6ed91d4 24 {
altasoul 0:6df0a6ed91d4 25 eth.address((char *) my_mac);
altasoul 0:6df0a6ed91d4 26 printf("MAC %02x:%02x:%02x:%02x:%02x:%02x\r\n",
altasoul 0:6df0a6ed91d4 27 my_mac[0], my_mac[1], my_mac[2], my_mac[3], my_mac[4], my_mac[5]);
altasoul 0:6df0a6ed91d4 28 memcpy(my_ip, ip, 4);
altasoul 0:6df0a6ed91d4 29 printf("IP %d.%d.%d.%d\r\n",
altasoul 0:6df0a6ed91d4 30 my_ip[0], my_ip[1], my_ip[2], my_ip[3]);
altasoul 0:6df0a6ed91d4 31 }
altasoul 0:6df0a6ed91d4 32
altasoul 0:6df0a6ed91d4 33 void Snet::handle_arp_request(uint8_t *buf, int len) {
altasoul 0:6df0a6ed91d4 34 #if 0
altasoul 0:6df0a6ed91d4 35 printf("Arp from %02x:%02x:%02x:%02x:%02x:%02x ",
altasoul 0:6df0a6ed91d4 36 buf[ENET_SMAC_O+0], buf[ENET_SMAC_O+1],
altasoul 0:6df0a6ed91d4 37 buf[ENET_SMAC_O+2], buf[ENET_SMAC_O+3],
altasoul 0:6df0a6ed91d4 38 buf[ENET_SMAC_O+4], buf[ENET_SMAC_O+5]);*/
altasoul 0:6df0a6ed91d4 39 #endif
altasoul 0:6df0a6ed91d4 40 eth.read((char *) &buf[ENET_PAYLOAD_O], len-ENET_PAYLOAD_O);
altasoul 0:6df0a6ed91d4 41 /*print_hex((uint8_t *) &buf[ENET_PAYLOAD_O], len-ENET_PAYLOAD_O);*/
altasoul 0:6df0a6ed91d4 42 if (!(memcmp(&buf[ENET_PAYLOAD_O], arp_req_payload_prefix, sizeof(arp_req_payload_prefix)) // ARP request
altasoul 0:6df0a6ed91d4 43 || memcmp(&buf[ENET_ARP_TPA_O], my_ip, sizeof(my_ip)))) { // for me
altasoul 0:6df0a6ed91d4 44 //ARP request for me. Build reply.
altasoul 0:6df0a6ed91d4 45 // Ethernet packet addresses:
altasoul 0:6df0a6ed91d4 46 memcpy(&buf[ENET_DMAC_O], &buf[ENET_SMAC_O], 6); // Back to sender
altasoul 0:6df0a6ed91d4 47 memcpy(&buf[ENET_SMAC_O], my_mac, 6); // from me
altasoul 0:6df0a6ed91d4 48 // ARP protocol packet:
altasoul 0:6df0a6ed91d4 49 buf[ENET_ARP_OPER_O+1] = 0x02; // we are replying
altasoul 0:6df0a6ed91d4 50 memcpy(&buf[ENET_ARP_THA_O], &buf[ENET_ARP_SHA_O], 6); // to hardware address of request sender
altasoul 0:6df0a6ed91d4 51 memcpy(&buf[ENET_ARP_TPA_O], &buf[ENET_ARP_SPA_O], 4); // to IP address of request sender
altasoul 0:6df0a6ed91d4 52 memcpy(&buf[ENET_ARP_SHA_O], my_mac, 6); // from my hardware address
altasoul 0:6df0a6ed91d4 53 memcpy(&buf[ENET_ARP_SPA_O], my_ip, 4); // and my IP address
altasoul 0:6df0a6ed91d4 54 //printf("ARP replying\r\n");
altasoul 0:6df0a6ed91d4 55 //print_hex((uint8_t *) buf, len);
altasoul 0:6df0a6ed91d4 56 eth.write((char *) buf, len);
altasoul 0:6df0a6ed91d4 57 eth.send();
altasoul 0:6df0a6ed91d4 58 };
altasoul 0:6df0a6ed91d4 59 };
altasoul 0:6df0a6ed91d4 60
altasoul 0:6df0a6ed91d4 61 void Snet::got_broadcast(uint8_t *buf, int len) {
altasoul 0:6df0a6ed91d4 62 #if 0
altasoul 0:6df0a6ed91d4 63 printf("Broadcast from: %02x:%02x:%02x:%02x:%02x:%02x type %02x%02x count %d\r\n",
altasoul 0:6df0a6ed91d4 64 buf[ENET_SMAC_O+0], buf[ENET_SMAC_O+1],
altasoul 0:6df0a6ed91d4 65 buf[ENET_SMAC_O+2], buf[ENET_SMAC_O+3],
altasoul 0:6df0a6ed91d4 66 buf[ENET_SMAC_O+4], buf[ENET_SMAC_O+5],
altasoul 0:6df0a6ed91d4 67 buf[ENET_ETHERTYPE_O+0], buf[ENET_ETHERTYPE_O+1],
altasoul 0:6df0a6ed91d4 68 enet_rx_int_cnt);
altasoul 0:6df0a6ed91d4 69 #endif
altasoul 0:6df0a6ed91d4 70 // ARP request?
altasoul 0:6df0a6ed91d4 71 if (buf[ENET_ETHERTYPE_O+0] == 0x08 && buf[ENET_ETHERTYPE_O+1] == 0x06)
altasoul 0:6df0a6ed91d4 72 handle_arp_request(buf, len);
altasoul 0:6df0a6ed91d4 73 };
altasoul 0:6df0a6ed91d4 74
altasoul 0:6df0a6ed91d4 75 void Snet::got_unicast(uint8_t *buf, int len) {
altasoul 0:6df0a6ed91d4 76 if (memcmp(&buf[ENET_ETHERTYPE_O], ipEtherType, 2)) return; // IP packets only from this point
altasoul 0:6df0a6ed91d4 77 // printf("Unicast from: %02x:%02x:%02x:%02x:%02x:%02x %d\r\n",
altasoul 0:6df0a6ed91d4 78 // buf[6], buf[7], buf[8], buf[9], buf[10], buf[11], enet_rx_int_cnt);
altasoul 0:6df0a6ed91d4 79 memcpy(correspondent_mac, &buf[ENET_SMAC_O], sizeof(correspondent_mac));
altasoul 0:6df0a6ed91d4 80 eth.read((char *) &buf[ENET_PAYLOAD_O], len-ENET_PAYLOAD_O); // Read in the whole rest of the packet
altasoul 0:6df0a6ed91d4 81 interpret_inet_packet(buf, len);
altasoul 0:6df0a6ed91d4 82 }
altasoul 0:6df0a6ed91d4 83
altasoul 1:9c211ac06a12 84 int Snet::rx_and_process_available_packets() {
altasoul 0:6df0a6ed91d4 85 #if 0
altasoul 1:9c211ac06a12 86 // if the MBED Ethernet worked correctly:
altasoul 0:6df0a6ed91d4 87 uint8_t buf[0x600];
altasoul 0:6df0a6ed91d4 88 #else
altasoul 0:6df0a6ed91d4 89 uint8_t buf[750+6+6+2]; // Experimentally-derived maximum packet size is 750 at the IP layer
altasoul 0:6df0a6ed91d4 90 #endif
altasoul 0:6df0a6ed91d4 91 int rv = 0;
altasoul 0:6df0a6ed91d4 92 int len;
altasoul 0:6df0a6ed91d4 93
altasoul 0:6df0a6ed91d4 94 while ((len = eth.receive()) > 0) {
altasoul 0:6df0a6ed91d4 95 eth.read((char *) buf, ENET_PAYLOAD_O); // destination MAC, source MAC, EtherType, lengcode
altasoul 0:6df0a6ed91d4 96 enet_rx_cnt++;
altasoul 0:6df0a6ed91d4 97 if (memcmp(&buf[ENET_DMAC_O], my_mac, 6) == 0) {
altasoul 0:6df0a6ed91d4 98 got_unicast(buf, len);
altasoul 0:6df0a6ed91d4 99 rv = 1;
altasoul 0:6df0a6ed91d4 100 } else if (memcmp(&buf[ENET_DMAC_O], broadcast_mac, 6) == 0) {
altasoul 0:6df0a6ed91d4 101 got_broadcast(buf, len);
altasoul 0:6df0a6ed91d4 102 rv = 2;
altasoul 0:6df0a6ed91d4 103 }
altasoul 0:6df0a6ed91d4 104 }
altasoul 0:6df0a6ed91d4 105 return rv;
altasoul 0:6df0a6ed91d4 106 }
altasoul 0:6df0a6ed91d4 107