184 lines
3.5 KiB
C
184 lines
3.5 KiB
C
/*
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* File: udp.c
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* Purpose: User Datagram Protocol driver
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*
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* Notes:
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*
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* Modifications:
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*
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*/
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#include "bas_types.h"
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#include "bas_printf.h"
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#include "net.h"
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#include <stddef.h>
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#define DBG_UDP
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#if defined(DBG_UDP)
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#define dbg(format, arg...) do { xprintf("DEBUG: " format "\r\n", ##arg); } while (0)
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#else
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#define dbg(format, arg...) do { ; } while (0)
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#endif /* DBG_UDP */
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typedef struct
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{
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uint16_t port;
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void (*handler)(NIF *, NBUF *);
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} UDP_BOUND_PORT;
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#define UDP_MAX_PORTS (5) /* plenty for this implementation */
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static UDP_BOUND_PORT udp_port_table[UDP_MAX_PORTS];
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static uint16_t udp_port;
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void udp_init(void)
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{
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int index;
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for (index = 0; index < UDP_MAX_PORTS; ++index)
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{
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udp_port_table[index].port = 0;
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}
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udp_port = DEFAULT_UDP_PORT; /* next free port */
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}
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void udp_prime_port(uint16_t init_port)
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{
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udp_port = init_port;
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}
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void udp_bind_port(uint16_t port, void (*handler)(NIF *, NBUF *))
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{
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int index;
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for (index = 0; index < UDP_MAX_PORTS; ++index)
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{
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if (udp_port_table[index].port == 0)
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{
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udp_port_table[index].port = port;
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udp_port_table[index].handler = handler;
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return;
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}
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}
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}
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void udp_free_port(uint16_t port)
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{
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int index;
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for (index = 0; index < UDP_MAX_PORTS; ++index)
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{
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if (udp_port_table[index].port == port)
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{
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udp_port_table[index].port = 0;
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return;
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}
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}
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}
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static void *udp_port_handler(uint16_t port)
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{
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int index;
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for (index = 0; index < UDP_MAX_PORTS; ++index)
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{
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if (udp_port_table[index].port == port)
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{
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return (void *)udp_port_table[index].handler;
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}
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}
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return NULL;
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}
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uint16_t udp_obtain_free_port(void)
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{
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uint16_t port;
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port = udp_port;
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if (--udp_port <= 255)
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udp_port = DEFAULT_UDP_PORT;
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return port;
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}
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int udp_send(NIF *nif, uint8_t *dest, int sport, int dport, NBUF *pNbuf)
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{
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uint8_t *myip;
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if (nif == NULL)
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{
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dbg("%s: nif is NULL\r\n", __FUNCTION__);
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return 0;
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}
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/*
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* This function takes data and creates a UDP frame and
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* passes it onto the IP layer
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*/
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udp_frame_hdr *udpframe;
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udpframe = (udp_frame_hdr *) &pNbuf->data[UDP_HDR_OFFSET];
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/* Set UDP source port */
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udpframe->src_port = (uint16_t) sport;
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/* Set UDP destination port */
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udpframe->dest_port = (uint16_t) dport;
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/* Set length */
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udpframe->length = (uint16_t) (pNbuf->length + UDP_HDR_SIZE);
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/* No checksum calcualation needed */
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udpframe->chksum = (uint16_t) 0;
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/* Add the length of the UDP packet to the total length of the packet */
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pNbuf->length += 8;
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myip = ip_get_myip(nif_get_protocol_info(nif, ETH_FRM_IP));
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dbg("%s: sent UDP request to %d.%d.%d.%d from %d.%d.%d.%d\r\n", __FUNCTION__,
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dest[0], dest[1], dest[2], dest[3],
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myip[0], myip[1], myip[2], myip[3]);
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return (ip_send(nif, dest, myip, IP_PROTO_UDP, pNbuf));
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}
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void udp_handler(NIF *nif, NBUF *pNbuf)
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{
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/*
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* This function handles incoming UDP packets
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*/
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udp_frame_hdr *udpframe;
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void (*handler)(NIF *, NBUF *);
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udpframe = (udp_frame_hdr *) &pNbuf->data[pNbuf->offset];
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dbg("%s: packet received\r\n", __FUNCTION__);
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/*
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* Adjust the length and valid data offset of the packet we are
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* passing on
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*/
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pNbuf->length -= UDP_HDR_SIZE;
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pNbuf->offset += UDP_HDR_SIZE;
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/*
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* Traverse the list of bound ports to see if there is a higher
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* level protocol to pass the packet on to
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*/
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if ((handler = (void(*)(NIF*, NBUF*)) udp_port_handler(UDP_DEST(udpframe))) != NULL)
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handler(nif, pNbuf);
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else
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{
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dbg("%s: received UDP packet for non-supported port\n", __FUNCTION__);
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nbuf_free(pNbuf);
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}
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return;
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}
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