69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/* ----------------------------------------------------------------------- *
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*
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* Copyright 2010 Intel Corporation; author: H. Peter Anvin
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston MA 02110-1301, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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#include <stdint.h>
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#include <stdbool.h>
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#include <netinet/in.h>
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#include "pxe.h"
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/* Port number bitmap - port numbers 49152 (0xc000) to 57343 (0xefff) */
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#define PORT_NUMBER_BASE 49152
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#define PORT_NUMBER_COUNT 8192 /* Power of 2, please */
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static uint32_t port_number_bitmap[PORT_NUMBER_COUNT/32];
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static uint16_t first_port_number /* = 0 */;
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/*
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* Bitmap functions
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*/
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static bool test_bit(const uint32_t *bitmap, int32_t index)
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{
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uint8_t st;
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asm("btl %2,%1 ; setc %0" : "=qm" (st) : "m" (*bitmap), "r" (index));
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return st;
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}
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static void set_bit(uint32_t *bitmap, int32_t index)
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{
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asm volatile("btsl %1,%0" : "+m" (*bitmap) : "r" (index) : "memory");
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}
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static void clr_bit(uint32_t *bitmap, int32_t index)
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{
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asm volatile("btcl %1,%0" : "+m" (*bitmap) : "r" (index) : "memory");
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}
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/*
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* Get and free a port number (host byte order)
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*/
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uint16_t get_port(void)
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{
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uint16_t port;
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do {
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port = first_port_number++;
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first_port_number &= PORT_NUMBER_COUNT - 1;
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} while (test_bit(port_number_bitmap, port));
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set_bit(port_number_bitmap, port);
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return htons(port + PORT_NUMBER_BASE);
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}
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void free_port(uint16_t port)
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{
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port = ntohs(port) - PORT_NUMBER_BASE;
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if (port >= PORT_NUMBER_COUNT)
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return;
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clr_bit(port_number_bitmap, port);
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}
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