diff options
Diffstat (limited to 'net/x25/x25_facilities.c')
| -rw-r--r-- | net/x25/x25_facilities.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c new file mode 100644 index 000000000..13759d1ea --- /dev/null +++ b/net/x25/x25_facilities.c @@ -0,0 +1,203 @@ +/* + * X.25 Packet Layer release 001 + * + * This is ALPHA test software. This code may break your machine, randomly fail to work with new + * releases, misbehave and/or generally screw up. It might even work. + * + * This code REQUIRES 2.1.15 or higher + * + * This module: + * This module is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * History + * X.25 001 Split from x25_subr.c + */ + +#include <linux/config.h> +#if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE) +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <net/sock.h> +#include <asm/segment.h> +#include <asm/system.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <net/x25.h> + +/* + * Parse a set of facilities into the facilities structure. Unrecognised + * facilities are written to the debug log file. + */ +int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities) +{ + unsigned int len; + unsigned char *p = skb->data; + + len = *p++; + + while (len > 0) { + switch (*p & X25_FAC_CLASS_MASK) { + case X25_FAC_CLASS_A: + switch (*p) { + case X25_FAC_REVERSE: + facilities->reverse = (p[1] & 0x01); + break; + case X25_FAC_THROUGHPUT: + facilities->throughput = p[1]; + break; + default: + printk(KERN_DEBUG "X.25: unknown facility %02X, value %02X\n", p[0], p[1]); + break; + } + p += 2; + len -= 2; + break; + + case X25_FAC_CLASS_B: + switch (*p) { + case X25_FAC_PACKET_SIZE: + facilities->pacsize_in = p[1]; + facilities->pacsize_out = p[2]; + break; + case X25_FAC_WINDOW_SIZE: + facilities->winsize_in = p[1]; + facilities->winsize_out = p[2]; + break; + default: + printk(KERN_DEBUG "X.25: unknown facility %02X, values %02X, %02X\n", p[0], p[1], p[2]); + break; + } + p += 3; + len -= 3; + break; + + case X25_FAC_CLASS_C: + printk(KERN_DEBUG "X.25: unknown facility %02X, values %02X, %02X, %02X\n", p[0], p[1], p[2], p[3]); + p += 4; + len -= 4; + break; + + case X25_FAC_CLASS_D: + printk(KERN_DEBUG "X.25: unknown facility %02X, length %d, values %02X, %02X, %02X, %02X\n", p[0], p[1], p[2], p[3], p[4], p[5]); + p += p[1] + 2; + len -= p[1] + 2; + break; + } + } + + return p - skb->data; +} + +/* + * Create a set of facilities. + */ +int x25_create_facilities(unsigned char *buffer, struct x25_facilities *facilities) +{ + unsigned char *p = buffer + 1; + int len; + + if (facilities->reverse != 0) { + *p++ = X25_FAC_REVERSE; + *p++ = (facilities->reverse) ? 0x01 : 0x00; + } + + if (facilities->throughput != 0) { + *p++ = X25_FAC_THROUGHPUT; + *p++ = facilities->throughput; + } + + if (facilities->pacsize_in != 0 || facilities->pacsize_out != 0) { + *p++ = X25_FAC_PACKET_SIZE; + *p++ = (facilities->pacsize_in == 0) ? facilities->pacsize_out : facilities->pacsize_in; + *p++ = (facilities->pacsize_out == 0) ? facilities->pacsize_in : facilities->pacsize_out; + } + + if (facilities->winsize_in != 0 || facilities->winsize_out != 0) { + *p++ = X25_FAC_WINDOW_SIZE; + *p++ = (facilities->winsize_in == 0) ? facilities->winsize_out : facilities->winsize_in; + *p++ = (facilities->winsize_out == 0) ? facilities->winsize_in : facilities->winsize_out; + } + + len = p - buffer; + buffer[0] = len - 1; + + return len; +} + +/* + * Try to reach a compromise on a set of facilities. + * + * The only real problem is with reverse charging. + */ +int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk, struct x25_facilities *new) +{ + struct x25_facilities *ours; + struct x25_facilities theirs; + int len; + + memset(&theirs, 0x00, sizeof(struct x25_facilities)); + + ours = &sk->protinfo.x25->facilities; + + *new = *ours; + + len = x25_parse_facilities(skb, &theirs); + + /* + * They want reverse charging, we won't accept it. + */ + if (theirs.reverse != 0 && ours->reverse == 0) { + SOCK_DEBUG(sk, "X.25: rejecting reverse charging request"); + return -1; + } + + new->reverse = theirs.reverse; + + if (theirs.throughput != 0) { + if (theirs.throughput < ours->throughput) { + SOCK_DEBUG(sk, "X.25: throughput negotiated down"); + new->throughput = theirs.throughput; + } + } + + if (theirs.pacsize_in != 0 && theirs.pacsize_out != 0) { + if (theirs.pacsize_in < ours->pacsize_in) { + SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down"); + new->pacsize_in = theirs.pacsize_in; + } + if (theirs.pacsize_out < ours->pacsize_out) { + SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down"); + new->pacsize_out = theirs.pacsize_out; + } + } + + if (theirs.winsize_in != 0 && theirs.winsize_out != 0) { + if (theirs.winsize_in < ours->winsize_in) { + SOCK_DEBUG(sk, "X.25: window size inwards negotiated down"); + new->winsize_in = theirs.winsize_in; + } + if (theirs.winsize_out < ours->winsize_out) { + SOCK_DEBUG(sk, "X.25: window size outwards negotiated down"); + new->winsize_out = theirs.winsize_out; + } + } + + return len; +} + +#endif |