646 lines
15 KiB
C
646 lines
15 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* The User Datagram Protocol (UDP).
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*
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* Version: @(#)udp.c 1.0.13 06/02/93
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*
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* Authors: Ross Biro, <bir7@leland.Stanford.Edu>
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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*
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* Fixes:
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* Alan Cox : verify_area() calls
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* Alan Cox : stopped close while in use off icmp
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* messages. Not a fix but a botch that
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* for udp at least is 'valid'.
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* Alan Cox : Fixed icmp handling properly
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* Alan Cox : Correct error for oversized datagrams
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* Alan Cox : Tidied select() semantics.
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* Alan Cox : udp_err() fixed properly, also now
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* select and read wake correctly on errors
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* Alan Cox : udp_send verify_area moved to avoid mem leak
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* Alan Cox : UDP can count its memory
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* Alan Cox : send to an uknown connection causes
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* an ECONNREFUSED off the icmp, but
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* does NOT close.
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* Alan Cox : Switched to new sk_buff handlers. No more backlog!
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* Alan Cox : Using generic datagram code. Even smaller and the PEEK
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* bug no longer crashes it.
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* Fred Van Kempen : Net2e support for sk->broadcast.
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* Alan Cox : Uses skb_free_datagram
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* Alan Cox : Added get/set sockopt support.
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* Alan Cox : Broadcasting without option set returns EACCES.
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* Alan Cox : No wakeup calls. Instead we now use the callbacks.
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* Alan Cox : Use ip_tos and ip_ttl
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <asm/system.h>
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#include <asm/segment.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/fcntl.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/timer.h>
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#include <linux/termios.h>
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#include <linux/mm.h>
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#include "inet.h"
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#include "dev.h"
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#include "ip.h"
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#include "protocol.h"
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#include "tcp.h"
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#include "skbuff.h"
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#include "sock.h"
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#include "udp.h"
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#include "icmp.h"
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#define min(a,b) ((a)<(b)?(a):(b))
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static void
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print_udp(struct udphdr *uh)
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{
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if (inet_debug != DBG_UDP) return;
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if (uh == NULL) {
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printk("(NULL)\n");
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return;
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}
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printk("UDP: source = %d, dest = %d\n", ntohs(uh->source), ntohs(uh->dest));
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printk(" len = %d, check = %d\n", ntohs(uh->len), ntohs(uh->check));
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}
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/*
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* This routine is called by the ICMP module when it gets some
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* sort of error condition. If err < 0 then the socket should
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* be closed and the error returned to the user. If err > 0
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* it's just the icmp type << 8 | icmp code.
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* Header points to the ip header of the error packet. We move
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* on past this. Then (as it used to claim before adjustment)
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* header points to the first 8 bytes of the udp header. We need
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* to find the appropriate port.
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*/
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void
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udp_err(int err, unsigned char *header, unsigned long daddr,
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unsigned long saddr, struct inet_protocol *protocol)
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{
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struct udphdr *th;
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struct sock *sk;
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struct iphdr *ip=(struct iphdr *)header;
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header += 4*ip->ihl;
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th = (struct udphdr *)header;
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DPRINTF((DBG_UDP,"UDP: err(err=%d, header=%X, daddr=%X, saddr=%X, protocl=%X)\n\
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sport=%d,dport=%d", err, header, daddr, saddr, protocol, (int)th->source,(int)th->dest));
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sk = get_sock(&udp_prot, th->source, daddr, th->dest, saddr);
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if (sk == NULL)
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return; /* No socket for error */
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if (err < 0) /* As per the calling spec */
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{
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sk->err = -err;
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sk->error_report(sk); /* User process wakes to see error */
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return;
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}
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if (err & 0xff00 ==(ICMP_SOURCE_QUENCH << 8)) { /* Slow down! */
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if (sk->cong_window > 1)
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sk->cong_window = sk->cong_window/2;
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return;
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}
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sk->err = icmp_err_convert[err & 0xff].errno;
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/* It's only fatal if we have connected to them. */
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if (icmp_err_convert[err & 0xff].fatal && sk->state == TCP_ESTABLISHED) {
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sk->err=ECONNREFUSED;
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}
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sk->error_report(sk);
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}
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static unsigned short
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udp_check(struct udphdr *uh, int len,
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unsigned long saddr, unsigned long daddr)
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{
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unsigned long sum;
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DPRINTF((DBG_UDP, "UDP: check(uh=%X, len = %d, saddr = %X, daddr = %X)\n",
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uh, len, saddr, daddr));
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print_udp(uh);
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__asm__("\t addl %%ecx,%%ebx\n"
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"\t adcl %%edx,%%ebx\n"
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"\t adcl $0, %%ebx\n"
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: "=b"(sum)
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: "0"(daddr), "c"(saddr), "d"((ntohs(len) << 16) + IPPROTO_UDP*256)
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: "cx","bx","dx" );
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if (len > 3) {
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__asm__("\tclc\n"
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"1:\n"
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"\t lodsl\n"
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"\t adcl %%eax, %%ebx\n"
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"\t loop 1b\n"
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"\t adcl $0, %%ebx\n"
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: "=b"(sum) , "=S"(uh)
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: "0"(sum), "c"(len/4) ,"1"(uh)
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: "ax", "cx", "bx", "si" );
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}
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/* Convert from 32 bits to 16 bits. */
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__asm__("\t movl %%ebx, %%ecx\n"
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"\t shrl $16,%%ecx\n"
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"\t addw %%cx, %%bx\n"
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"\t adcw $0, %%bx\n"
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: "=b"(sum)
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: "0"(sum)
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: "bx", "cx");
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/* Check for an extra word. */
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if ((len & 2) != 0) {
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__asm__("\t lodsw\n"
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"\t addw %%ax,%%bx\n"
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"\t adcw $0, %%bx\n"
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: "=b"(sum), "=S"(uh)
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: "0"(sum) ,"1"(uh)
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: "si", "ax", "bx");
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}
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/* Now check for the extra byte. */
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if ((len & 1) != 0) {
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__asm__("\t lodsb\n"
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"\t movb $0,%%ah\n"
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"\t addw %%ax,%%bx\n"
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"\t adcw $0, %%bx\n"
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: "=b"(sum)
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: "0"(sum) ,"S"(uh)
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: "si", "ax", "bx");
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}
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/* We only want the bottom 16 bits, but we never cleared the top 16. */
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return((~sum) & 0xffff);
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}
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static void
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udp_send_check(struct udphdr *uh, unsigned long saddr,
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unsigned long daddr, int len, struct sock *sk)
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{
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uh->check = 0;
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if (sk && sk->no_check)
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return;
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uh->check = udp_check(uh, len, saddr, daddr);
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if (uh->check == 0) uh->check = 0xffff;
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}
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static int
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udp_send(struct sock *sk, struct sockaddr_in *sin,
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unsigned char *from, int len)
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{
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struct sk_buff *skb;
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struct device *dev;
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struct udphdr *uh;
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unsigned char *buff;
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unsigned long saddr;
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int size, tmp;
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int err;
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DPRINTF((DBG_UDP, "UDP: send(dst=%s:%d buff=%X len=%d)\n",
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in_ntoa(sin->sin_addr.s_addr), ntohs(sin->sin_port),
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from, len));
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err=verify_area(VERIFY_READ, from, len);
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if(err)
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return(err);
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/* Allocate a copy of the packet. */
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size = sizeof(struct sk_buff) + sk->prot->max_header + len;
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skb = sk->prot->wmalloc(sk, size, 0, GFP_KERNEL);
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if (skb == NULL) return(-ENOMEM);
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skb->mem_addr = skb;
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skb->mem_len = size;
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skb->sk = NULL; /* to avoid changing sk->saddr */
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skb->free = 1;
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skb->arp = 0;
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/* Now build the IP and MAC header. */
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buff = skb->data;
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saddr = 0;
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dev = NULL;
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DPRINTF((DBG_UDP, "UDP: >> IP_Header: %X -> %X dev=%X prot=%X len=%d\n",
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saddr, sin->sin_addr.s_addr, dev, IPPROTO_UDP, skb->mem_len));
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tmp = sk->prot->build_header(skb, saddr, sin->sin_addr.s_addr,
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&dev, IPPROTO_UDP, sk->opt, skb->mem_len,sk->ip_tos,sk->ip_ttl);
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skb->sk=sk; /* So memory is freed correctly */
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if (tmp < 0 ) {
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sk->prot->wfree(sk, skb->mem_addr, skb->mem_len);
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return(tmp);
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}
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buff += tmp;
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saddr = dev->pa_addr;
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DPRINTF((DBG_UDP, "UDP: >> MAC+IP len=%d\n", tmp));
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skb->len = tmp + sizeof(struct udphdr) + len; /* len + UDP + IP + MAC */
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skb->dev = dev;
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#ifdef OLD
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/*
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* This code used to hack in some form of fragmentation.
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* I removed that, since it didn't work anyway, and it made the
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* code a bad thing to read and understand. -FvK
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*/
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if (len > dev->mtu) {
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#else
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if (skb->len > 4095)
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{
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#endif
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printk("UDP: send: length %d > mtu %d (ignored)\n", len, dev->mtu);
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sk->prot->wfree(sk, skb->mem_addr, skb->mem_len);
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return(-EMSGSIZE);
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}
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/* Fill in the UDP header. */
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uh = (struct udphdr *) buff;
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uh->len = htons(len + sizeof(struct udphdr));
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uh->source = sk->dummy_th.source;
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uh->dest = sin->sin_port;
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buff = (unsigned char *) (uh + 1);
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/* Copy the user data. */
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memcpy_fromfs(buff, from, len);
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/* Set up the UDP checksum. */
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udp_send_check(uh, saddr, sin->sin_addr.s_addr, skb->len - tmp, sk);
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/* Send the datagram to the interface. */
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sk->prot->queue_xmit(sk, dev, skb, 1);
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return(len);
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}
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static int
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udp_sendto(struct sock *sk, unsigned char *from, int len, int noblock,
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unsigned flags, struct sockaddr_in *usin, int addr_len)
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{
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struct sockaddr_in sin;
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int tmp;
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int err;
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DPRINTF((DBG_UDP, "UDP: sendto(len=%d, flags=%X)\n", len, flags));
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/* Check the flags. */
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if (flags)
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return(-EINVAL);
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if (len < 0)
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return(-EINVAL);
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if (len == 0)
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return(0);
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/* Get and verify the address. */
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if (usin) {
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if (addr_len < sizeof(sin)) return(-EINVAL);
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err=verify_area(VERIFY_READ, usin, sizeof(sin));
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if(err)
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return err;
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memcpy_fromfs(&sin, usin, sizeof(sin));
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if (sin.sin_family && sin.sin_family != AF_INET)
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return(-EINVAL);
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if (sin.sin_port == 0)
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return(-EINVAL);
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} else {
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if (sk->state != TCP_ESTABLISHED) return(-EINVAL);
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sin.sin_family = AF_INET;
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sin.sin_port = sk->dummy_th.dest;
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sin.sin_addr.s_addr = sk->daddr;
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}
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if(!sk->broadcast && chk_addr(sin.sin_addr.s_addr)==IS_BROADCAST)
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return -EACCES; /* Must turn broadcast on first */
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sk->inuse = 1;
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/* Send the packet. */
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tmp = udp_send(sk, &sin, from, len);
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/* The datagram has been sent off. Release the socket. */
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release_sock(sk);
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return(tmp);
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}
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static int
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udp_write(struct sock *sk, unsigned char *buff, int len, int noblock,
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unsigned flags)
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{
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return(udp_sendto(sk, buff, len, noblock, flags, NULL, 0));
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}
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int
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udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
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{
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int err;
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switch(cmd) {
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case DDIOCSDBG:
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{
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int val;
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if (!suser()) return(-EPERM);
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err=verify_area(VERIFY_READ, (void *)arg, sizeof(int));
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if(err)
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return err;
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val = get_fs_long((int *)arg);
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switch(val) {
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case 0:
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inet_debug = 0;
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break;
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case 1:
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inet_debug = DBG_UDP;
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break;
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default:
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return(-EINVAL);
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}
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}
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break;
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case TIOCOUTQ:
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{
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unsigned long amount;
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if (sk->state == TCP_LISTEN) return(-EINVAL);
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amount = sk->prot->wspace(sk)/*/2*/;
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err=verify_area(VERIFY_WRITE,(void *)arg,
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sizeof(unsigned long));
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if(err)
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return(err);
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put_fs_long(amount,(unsigned long *)arg);
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return(0);
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}
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case TIOCINQ:
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{
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struct sk_buff *skb;
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unsigned long amount;
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if (sk->state == TCP_LISTEN) return(-EINVAL);
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amount = 0;
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skb = sk->rqueue;
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if (skb != NULL) {
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/*
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* We will only return the amount
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* of this packet since that is all
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* that will be read.
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*/
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amount = skb->len;
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}
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err=verify_area(VERIFY_WRITE,(void *)arg,
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sizeof(unsigned long));
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if(err)
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return(err);
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put_fs_long(amount,(unsigned long *)arg);
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return(0);
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}
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default:
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return(-EINVAL);
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}
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return(0);
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}
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/*
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* This should be easy, if there is something there we\
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* return it, otherwise we block.
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*/
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int
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udp_recvfrom(struct sock *sk, unsigned char *to, int len,
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int noblock, unsigned flags, struct sockaddr_in *sin,
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int *addr_len)
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{
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int copied = 0;
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struct sk_buff *skb;
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int er;
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/*
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* This will pick up errors that occured while the program
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* was doing something else.
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*/
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if (sk->err) {
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int err;
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err = -sk->err;
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sk->err = 0;
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return(err);
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}
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if (len == 0)
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return(0);
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if (len < 0)
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return(-EINVAL);
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if (addr_len) {
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er=verify_area(VERIFY_WRITE, addr_len, sizeof(*addr_len));
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if(er)
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return(er);
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put_fs_long(sizeof(*sin), addr_len);
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}
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if(sin)
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{
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er=verify_area(VERIFY_WRITE, sin, sizeof(*sin));
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if(er)
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return(er);
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}
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er=verify_area(VERIFY_WRITE,to,len);
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if(er)
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return er;
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skb=skb_recv_datagram(sk,flags,noblock,&er);
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if(skb==NULL)
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return er;
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copied = min(len, skb->len);
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/* FIXME : should use udp header size info value */
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skb_copy_datagram(skb,sizeof(struct udphdr),to,copied);
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/* Copy the address. */
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if (sin) {
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struct sockaddr_in addr;
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addr.sin_family = AF_INET;
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addr.sin_port = skb->h.uh->source;
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addr.sin_addr.s_addr = skb->daddr;
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memcpy_tofs(sin, &addr, sizeof(*sin));
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}
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skb_free_datagram(skb);
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release_sock(sk);
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return(copied);
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}
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int
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udp_read(struct sock *sk, unsigned char *buff, int len, int noblock,
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unsigned flags)
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{
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return(udp_recvfrom(sk, buff, len, noblock, flags, NULL, NULL));
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}
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int
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udp_connect(struct sock *sk, struct sockaddr_in *usin, int addr_len)
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{
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struct sockaddr_in sin;
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int er;
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if (addr_len < sizeof(sin))
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return(-EINVAL);
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er=verify_area(VERIFY_READ, usin, sizeof(sin));
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if(er)
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return er;
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memcpy_fromfs(&sin, usin, sizeof(sin));
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if (sin.sin_family && sin.sin_family != AF_INET)
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return(-EAFNOSUPPORT);
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if(!sk->broadcast && chk_addr(sin.sin_addr.s_addr)==IS_BROADCAST)
|
|
return -EACCES; /* Must turn broadcast on first */
|
|
|
|
sk->daddr = sin.sin_addr.s_addr;
|
|
sk->dummy_th.dest = sin.sin_port;
|
|
sk->state = TCP_ESTABLISHED;
|
|
return(0);
|
|
}
|
|
|
|
|
|
static void
|
|
udp_close(struct sock *sk, int timeout)
|
|
{
|
|
sk->inuse = 1;
|
|
sk->state = TCP_CLOSE;
|
|
if (sk->dead) destroy_sock(sk);
|
|
else release_sock(sk);
|
|
}
|
|
|
|
|
|
/* All we need to do is get the socket, and then do a checksum. */
|
|
int
|
|
udp_rcv(struct sk_buff *skb, struct device *dev, struct options *opt,
|
|
unsigned long daddr, unsigned short len,
|
|
unsigned long saddr, int redo, struct inet_protocol *protocol)
|
|
{
|
|
struct sock *sk;
|
|
struct udphdr *uh;
|
|
|
|
uh = (struct udphdr *) skb->h.uh;
|
|
sk = get_sock(&udp_prot, uh->dest, saddr, uh->source, daddr);
|
|
if (sk == NULL)
|
|
{
|
|
if (chk_addr(daddr) == IS_MYADDR)
|
|
{
|
|
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, dev);
|
|
}
|
|
/*
|
|
* Hmm. We got an UDP broadcast to a port to which we
|
|
* don't wanna listen. The only thing we can do now is
|
|
* to ignore the packet... -FvK
|
|
*/
|
|
skb->sk = NULL;
|
|
kfree_skb(skb, FREE_WRITE);
|
|
return(0);
|
|
}
|
|
|
|
if (uh->check && udp_check(uh, len, saddr, daddr)) {
|
|
DPRINTF((DBG_UDP, "UDP: bad checksum\n"));
|
|
skb->sk = NULL;
|
|
kfree_skb(skb, FREE_WRITE);
|
|
return(0);
|
|
}
|
|
|
|
skb->sk = sk;
|
|
skb->dev = dev;
|
|
skb->len = len;
|
|
|
|
/* These are supposed to be switched. */
|
|
skb->daddr = saddr;
|
|
skb->saddr = daddr;
|
|
|
|
|
|
/* Charge it to the socket. */
|
|
if (sk->rmem_alloc + skb->mem_len >= sk->rcvbuf)
|
|
{
|
|
skb->sk = NULL;
|
|
kfree_skb(skb, FREE_WRITE);
|
|
release_sock(sk);
|
|
return(0);
|
|
}
|
|
sk->rmem_alloc += skb->mem_len;
|
|
|
|
/* At this point we should print the thing out. */
|
|
DPRINTF((DBG_UDP, "<< \n"));
|
|
print_udp(uh);
|
|
|
|
/* Now add it to the data chain and wake things up. */
|
|
|
|
skb_queue_tail(&sk->rqueue,skb);
|
|
|
|
skb->len = len - sizeof(*uh);
|
|
|
|
if (!sk->dead)
|
|
sk->data_ready(sk,skb->len);
|
|
|
|
release_sock(sk);
|
|
return(0);
|
|
}
|
|
|
|
|
|
struct proto udp_prot = {
|
|
sock_wmalloc,
|
|
sock_rmalloc,
|
|
sock_wfree,
|
|
sock_rfree,
|
|
sock_rspace,
|
|
sock_wspace,
|
|
udp_close,
|
|
udp_read,
|
|
udp_write,
|
|
udp_sendto,
|
|
udp_recvfrom,
|
|
ip_build_header,
|
|
udp_connect,
|
|
NULL,
|
|
ip_queue_xmit,
|
|
ip_retransmit,
|
|
NULL,
|
|
NULL,
|
|
udp_rcv,
|
|
datagram_select,
|
|
udp_ioctl,
|
|
NULL,
|
|
NULL,
|
|
ip_setsockopt,
|
|
ip_getsockopt,
|
|
128,
|
|
0,
|
|
{NULL,},
|
|
"UDP"
|
|
};
|