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@0:6df0a6ed91d4, 2015-03-04 (annotated)

Committer:
altasoul
Date:
Wed Mar 04 02:04:32 2015 +0000
Revision:
0:6df0a6ed91d4
Child:
1:9c211ac06a12
refactor into Snet

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 extern uint8_t my_ip[4];
altasoul 0:6df0a6ed91d4 11
altasoul 0:6df0a6ed91d4 12
altasoul 0:6df0a6ed91d4 13 //uint8_t correspondent_mac[6]; // correspondent's MAC
altasoul 0:6df0a6ed91d4 14 const uint8_t Snet::broadcast_mac[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
altasoul 0:6df0a6ed91d4 15 //const char ourEtherType[] = { 0x82, 0x48 };
altasoul 0:6df0a6ed91d4 16 const uint8_t Snet::ipEtherType[] = { 0x08, 0x00 };
altasoul 0:6df0a6ed91d4 17 const uint8_t Snet::arp_req_payload_prefix[] = { 0x0, 0x1, 0x8, 0x0, 0x6, 0x4, 0x0, 0x1 };
altasoul 0:6df0a6ed91d4 18
altasoul 0:6df0a6ed91d4 19 extern void interpret_inet_packet(uint8_t *buf, int len);
altasoul 0:6df0a6ed91d4 20 extern void send_packet_to_radio(uint8_t const *, int);
altasoul 0:6df0a6ed91d4 21
altasoul 0:6df0a6ed91d4 22
altasoul 0:6df0a6ed91d4 23
altasoul 0:6df0a6ed91d4 24 Snet::Snet(): eth()
altasoul 0:6df0a6ed91d4 25 {
altasoul 0:6df0a6ed91d4 26 eth.address((char *) my_mac);
altasoul 0:6df0a6ed91d4 27 printf("MAC %02x:%02x:%02x:%02x:%02x:%02x\r\n",
altasoul 0:6df0a6ed91d4 28 my_mac[0], my_mac[1], my_mac[2], my_mac[3], my_mac[4], my_mac[5]);
altasoul 0:6df0a6ed91d4 29 printf("no IP\r\n");
altasoul 0:6df0a6ed91d4 30 #if 0 // FIXME
altasoul 0:6df0a6ed91d4 31 LPC_EMAC->IntEnable = 0; // disable all Ethernet interrupts
altasoul 0:6df0a6ed91d4 32 LPC_EMAC->IntClear = ~0; // clear all interrupts
altasoul 0:6df0a6ed91d4 33
altasoul 0:6df0a6ed91d4 34 //enet_rx_balance = 0;
altasoul 0:6df0a6ed91d4 35 // Enable Ethernet TX and RX Packet Interrupts:
altasoul 0:6df0a6ed91d4 36 //LPC_EMAC->IntEnable |= (ETH_RxFinishedInt | ETH_TxFinishedInt);
altasoul 0:6df0a6ed91d4 37 LPC_EMAC->IntEnable |= (ETH_RxDoneInt | ETH_TxDoneInt);
altasoul 0:6df0a6ed91d4 38 NVIC_SetPriority(ENET_IRQn, 0); // lower numbers have priority
altasoul 0:6df0a6ed91d4 39
altasoul 0:6df0a6ed91d4 40 // Enable the interrupt.
altasoul 0:6df0a6ed91d4 41 NVIC_EnableIRQ(ENET_IRQn);
altasoul 0:6df0a6ed91d4 42 #endif
altasoul 0:6df0a6ed91d4 43 }
altasoul 0:6df0a6ed91d4 44
altasoul 0:6df0a6ed91d4 45 Snet::Snet(const uint8_t *ip): eth()
altasoul 0:6df0a6ed91d4 46 {
altasoul 0:6df0a6ed91d4 47 eth.address((char *) my_mac);
altasoul 0:6df0a6ed91d4 48 printf("MAC %02x:%02x:%02x:%02x:%02x:%02x\r\n",
altasoul 0:6df0a6ed91d4 49 my_mac[0], my_mac[1], my_mac[2], my_mac[3], my_mac[4], my_mac[5]);
altasoul 0:6df0a6ed91d4 50 memcpy(my_ip, ip, 4);
altasoul 0:6df0a6ed91d4 51 printf("IP %d.%d.%d.%d\r\n",
altasoul 0:6df0a6ed91d4 52 my_ip[0], my_ip[1], my_ip[2], my_ip[3]);
altasoul 0:6df0a6ed91d4 53 #if 0 // FIXME
altasoul 0:6df0a6ed91d4 54 LPC_EMAC->IntEnable = 0; // disable all Ethernet interrupts
altasoul 0:6df0a6ed91d4 55 LPC_EMAC->IntClear = ~0; // clear all interrupts
altasoul 0:6df0a6ed91d4 56
altasoul 0:6df0a6ed91d4 57 //enet_rx_balance = 0;
altasoul 0:6df0a6ed91d4 58 // Enable Ethernet TX and RX Packet Interrupts:
altasoul 0:6df0a6ed91d4 59 //LPC_EMAC->IntEnable |= (ETH_RxFinishedInt | ETH_TxFinishedInt);
altasoul 0:6df0a6ed91d4 60 LPC_EMAC->IntEnable |= (ETH_RxDoneInt | ETH_TxDoneInt);
altasoul 0:6df0a6ed91d4 61 NVIC_SetPriority(ENET_IRQn, 0); // lower numbers have priority
altasoul 0:6df0a6ed91d4 62
altasoul 0:6df0a6ed91d4 63 // Enable the interrupt.
altasoul 0:6df0a6ed91d4 64 NVIC_EnableIRQ(ENET_IRQn);
altasoul 0:6df0a6ed91d4 65 #endif
altasoul 0:6df0a6ed91d4 66 }
altasoul 0:6df0a6ed91d4 67
altasoul 0:6df0a6ed91d4 68
altasoul 0:6df0a6ed91d4 69
altasoul 0:6df0a6ed91d4 70 void Snet::handle_arp_request(uint8_t *buf, int len) {
altasoul 0:6df0a6ed91d4 71 #if 0
altasoul 0:6df0a6ed91d4 72 printf("Arp from %02x:%02x:%02x:%02x:%02x:%02x ",
altasoul 0:6df0a6ed91d4 73 buf[ENET_SMAC_O+0], buf[ENET_SMAC_O+1],
altasoul 0:6df0a6ed91d4 74 buf[ENET_SMAC_O+2], buf[ENET_SMAC_O+3],
altasoul 0:6df0a6ed91d4 75 buf[ENET_SMAC_O+4], buf[ENET_SMAC_O+5]);*/
altasoul 0:6df0a6ed91d4 76 #endif
altasoul 0:6df0a6ed91d4 77 eth.read((char *) &buf[ENET_PAYLOAD_O], len-ENET_PAYLOAD_O);
altasoul 0:6df0a6ed91d4 78 /*print_hex((uint8_t *) &buf[ENET_PAYLOAD_O], len-ENET_PAYLOAD_O);*/
altasoul 0:6df0a6ed91d4 79 if (!(memcmp(&buf[ENET_PAYLOAD_O], arp_req_payload_prefix, sizeof(arp_req_payload_prefix)) // ARP request
altasoul 0:6df0a6ed91d4 80 || memcmp(&buf[ENET_ARP_TPA_O], my_ip, sizeof(my_ip)))) { // for me
altasoul 0:6df0a6ed91d4 81 //ARP request for me. Build reply.
altasoul 0:6df0a6ed91d4 82 // Ethernet packet addresses:
altasoul 0:6df0a6ed91d4 83 memcpy(&buf[ENET_DMAC_O], &buf[ENET_SMAC_O], 6); // Back to sender
altasoul 0:6df0a6ed91d4 84 memcpy(&buf[ENET_SMAC_O], my_mac, 6); // from me
altasoul 0:6df0a6ed91d4 85 // ARP protocol packet:
altasoul 0:6df0a6ed91d4 86 buf[ENET_ARP_OPER_O+1] = 0x02; // we are replying
altasoul 0:6df0a6ed91d4 87 memcpy(&buf[ENET_ARP_THA_O], &buf[ENET_ARP_SHA_O], 6); // to hardware address of request sender
altasoul 0:6df0a6ed91d4 88 memcpy(&buf[ENET_ARP_TPA_O], &buf[ENET_ARP_SPA_O], 4); // to IP address of request sender
altasoul 0:6df0a6ed91d4 89 memcpy(&buf[ENET_ARP_SHA_O], my_mac, 6); // from my hardware address
altasoul 0:6df0a6ed91d4 90 memcpy(&buf[ENET_ARP_SPA_O], my_ip, 4); // and my IP address
altasoul 0:6df0a6ed91d4 91 //printf("ARP replying\r\n");
altasoul 0:6df0a6ed91d4 92 //print_hex((uint8_t *) buf, len);
altasoul 0:6df0a6ed91d4 93 eth.write((char *) buf, len);
altasoul 0:6df0a6ed91d4 94 eth.send();
altasoul 0:6df0a6ed91d4 95 };
altasoul 0:6df0a6ed91d4 96 };
altasoul 0:6df0a6ed91d4 97
altasoul 0:6df0a6ed91d4 98 void Snet::got_broadcast(uint8_t *buf, int len) {
altasoul 0:6df0a6ed91d4 99 #if 0
altasoul 0:6df0a6ed91d4 100 printf("Broadcast from: %02x:%02x:%02x:%02x:%02x:%02x type %02x%02x count %d\r\n",
altasoul 0:6df0a6ed91d4 101 buf[ENET_SMAC_O+0], buf[ENET_SMAC_O+1],
altasoul 0:6df0a6ed91d4 102 buf[ENET_SMAC_O+2], buf[ENET_SMAC_O+3],
altasoul 0:6df0a6ed91d4 103 buf[ENET_SMAC_O+4], buf[ENET_SMAC_O+5],
altasoul 0:6df0a6ed91d4 104 buf[ENET_ETHERTYPE_O+0], buf[ENET_ETHERTYPE_O+1],
altasoul 0:6df0a6ed91d4 105 enet_rx_int_cnt);
altasoul 0:6df0a6ed91d4 106 #endif
altasoul 0:6df0a6ed91d4 107 // ARP request?
altasoul 0:6df0a6ed91d4 108 if (buf[ENET_ETHERTYPE_O+0] == 0x08 && buf[ENET_ETHERTYPE_O+1] == 0x06)
altasoul 0:6df0a6ed91d4 109 handle_arp_request(buf, len);
altasoul 0:6df0a6ed91d4 110 };
altasoul 0:6df0a6ed91d4 111
altasoul 0:6df0a6ed91d4 112 void Snet::got_unicast(uint8_t *buf, int len) {
altasoul 0:6df0a6ed91d4 113 if (memcmp(&buf[ENET_ETHERTYPE_O], ipEtherType, 2)) return; // IP packets only from this point
altasoul 0:6df0a6ed91d4 114 // printf("Unicast from: %02x:%02x:%02x:%02x:%02x:%02x %d\r\n",
altasoul 0:6df0a6ed91d4 115 // buf[6], buf[7], buf[8], buf[9], buf[10], buf[11], enet_rx_int_cnt);
altasoul 0:6df0a6ed91d4 116 memcpy(correspondent_mac, &buf[ENET_SMAC_O], sizeof(correspondent_mac));
altasoul 0:6df0a6ed91d4 117 eth.read((char *) &buf[ENET_PAYLOAD_O], len-ENET_PAYLOAD_O); // Read in the whole rest of the packet
altasoul 0:6df0a6ed91d4 118 interpret_inet_packet(buf, len);
altasoul 0:6df0a6ed91d4 119 }
altasoul 0:6df0a6ed91d4 120
altasoul 0:6df0a6ed91d4 121 int Snet::rx_and_process_one_packet() {
altasoul 0:6df0a6ed91d4 122 #if 0
altasoul 0:6df0a6ed91d4 123 // if the damn Ethernet worked correctly:
altasoul 0:6df0a6ed91d4 124 uint8_t buf[0x600];
altasoul 0:6df0a6ed91d4 125 #else
altasoul 0:6df0a6ed91d4 126 uint8_t buf[750+6+6+2]; // Experimentally-derived maximum packet size is 750 at the IP layer
altasoul 0:6df0a6ed91d4 127 #endif
altasoul 0:6df0a6ed91d4 128 int rv = 0;
altasoul 0:6df0a6ed91d4 129 int len;
altasoul 0:6df0a6ed91d4 130
altasoul 0:6df0a6ed91d4 131 while ((len = eth.receive()) > 0) {
altasoul 0:6df0a6ed91d4 132 eth.read((char *) buf, ENET_PAYLOAD_O); // destination MAC, source MAC, EtherType, lengcode
altasoul 0:6df0a6ed91d4 133 enet_rx_cnt++;
altasoul 0:6df0a6ed91d4 134 if (memcmp(&buf[ENET_DMAC_O], my_mac, 6) == 0) {
altasoul 0:6df0a6ed91d4 135 got_unicast(buf, len);
altasoul 0:6df0a6ed91d4 136 rv = 1;
altasoul 0:6df0a6ed91d4 137 } else if (memcmp(&buf[ENET_DMAC_O], broadcast_mac, 6) == 0) {
altasoul 0:6df0a6ed91d4 138 got_broadcast(buf, len);
altasoul 0:6df0a6ed91d4 139 rv = 2;
altasoul 0:6df0a6ed91d4 140 }
altasoul 0:6df0a6ed91d4 141 }
altasoul 0:6df0a6ed91d4 142 return rv;
altasoul 0:6df0a6ed91d4 143 }
altasoul 0:6df0a6ed91d4 144