/* * X.25 Packet Layer release 002 * * 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 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities * negotiation. * apr/14/05 Shaun Pereira - Allow fast select with no restriction * on response. */ #include #include #include #include #include /* * Parse a set of facilities into the facilities structures. Unrecognised * facilities are written to the debug log file. */ int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities, struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask) { unsigned char *p = skb->data; unsigned int len = *p++; *vc_fac_mask = 0; /* * The kernel knows which facilities were set on an incoming call but * currently this information is not available to userspace. Here we * give userspace who read incoming call facilities 0 length to indicate * it wasn't set. */ dte_facs->calling_len = 0; dte_facs->called_len = 0; memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae)); memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae)); while (len > 0) { switch (*p & X25_FAC_CLASS_MASK) { case X25_FAC_CLASS_A: switch (*p) { case X25_FAC_REVERSE: if((p[1] & 0x81) == 0x81) { facilities->reverse = p[1] & 0x81; *vc_fac_mask |= X25_MASK_REVERSE; break; } if((p[1] & 0x01) == 0x01) { facilities->reverse = p[1] & 0x01; *vc_fac_mask |= X25_MASK_REVERSE; break; } if((p[1] & 0x80) == 0x80) { facilities->reverse = p[1] & 0x80; *vc_fac_mask |= X25_MASK_REVERSE; break; } if(p[1] == 0x00) { facilities->reverse = X25_DEFAULT_REVERSE; *vc_fac_mask |= X25_MASK_REVERSE; break; } case X25_FAC_THROUGHPUT: facilities->throughput = p[1]; *vc_fac_mask |= X25_MASK_THROUGHPUT; break; case X25_MARKER: 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]; *vc_fac_mask |= X25_MASK_PACKET_SIZE; break; case X25_FAC_WINDOW_SIZE: facilities->winsize_in = p[1]; facilities->winsize_out = p[2]; *vc_fac_mask |= X25_MASK_WINDOW_SIZE; 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: switch (*p) { case X25_FAC_CALLING_AE: if (p[1] > X25_MAX_DTE_FACIL_LEN) break; dte_facs->calling_len = p[2]; memcpy(dte_facs->calling_ae, &p[3], p[1] - 1); *vc_fac_mask |= X25_MASK_CALLING_AE; break; case X25_FAC_CALLED_AE: if (p[1] > X25_MAX_DTE_FACIL_LEN) break; dte_facs->called_len = p[2]; memcpy(dte_facs->called_ae, &p[3], p[1] - 1); *vc_fac_mask |= X25_MASK_CALLED_AE; break; default: 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]); break; } len -= p[1] + 2; p += p[1] + 2; break; } } return p - skb->data; } /* * Create a set of facilities. */ int x25_create_facilities(unsigned char *buffer, struct x25_facilities *facilities, struct x25_dte_facilities *dte_facs, unsigned long facil_mask) { unsigned char *p = buffer + 1; int len; if (!facil_mask) { /* * Length of the facilities field in call_req or * call_accept packets */ buffer[0] = 0; len = 1; /* 1 byte for the length field */ return len; } if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) { *p++ = X25_FAC_REVERSE; *p++ = facilities->reverse; } if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) { *p++ = X25_FAC_THROUGHPUT; *p++ = facilities->throughput; } if ((facilities->pacsize_in || facilities->pacsize_out) && (facil_mask & X25_MASK_PACKET_SIZE)) { *p++ = X25_FAC_PACKET_SIZE; *p++ = facilities->pacsize_in ? : facilities->pacsize_out; *p++ = facilities->pacsize_out ? : facilities->pacsize_in; } if ((facilities->winsize_in || facilities->winsize_out) && (facil_mask & X25_MASK_WINDOW_SIZE)) { *p++ = X25_FAC_WINDOW_SIZE; *p++ = facilities->winsize_in ? : facilities->winsize_out; *p++ = facilities->winsize_out ? : facilities->winsize_in; } if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) { *p++ = X25_MARKER; *p++ = X25_DTE_SERVICES; } if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) { unsigned bytecount = (dte_facs->calling_len % 2) ? dte_facs->calling_len / 2 + 1 : dte_facs->calling_len / 2; *p++ = X25_FAC_CALLING_AE; *p++ = 1 + bytecount; *p++ = dte_facs->calling_len; memcpy(p, dte_facs->calling_ae, bytecount); p += bytecount; } if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) { unsigned bytecount = (dte_facs->called_len % 2) ? dte_facs->called_len / 2 + 1 : dte_facs->called_len / 2; *p++ = X25_FAC_CALLED_AE; *p++ = 1 + bytecount; *p++ = dte_facs->called_len; memcpy(p, dte_facs->called_ae, bytecount); p+=bytecount; } 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_dte_facilities *dte) { struct x25_sock *x25 = x25_sk(sk); struct x25_facilities *ours = &x25->facilities; struct x25_facilities theirs; int len; memset(&theirs, 0, sizeof(theirs)); memcpy(new, ours, sizeof(*new)); len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask); /* * They want reverse charging, we won't accept it. */ if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) { SOCK_DEBUG(sk, "X.25: rejecting reverse charging request\n"); return -1; } new->reverse = theirs.reverse; if (theirs.throughput) { if (theirs.throughput < ours->throughput) { SOCK_DEBUG(sk, "X.25: throughput negotiated down\n"); new->throughput = theirs.throughput; } } if (theirs.pacsize_in && theirs.pacsize_out) { if (theirs.pacsize_in < ours->pacsize_in) { SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n"); new->pacsize_in = theirs.pacsize_in; } if (theirs.pacsize_out < ours->pacsize_out) { SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n"); new->pacsize_out = theirs.pacsize_out; } } if (theirs.winsize_in && theirs.winsize_out) { if (theirs.winsize_in < ours->winsize_in) { SOCK_DEBUG(sk, "X.25: window size inwards negotiated down\n"); new->winsize_in = theirs.winsize_in; } if (theirs.winsize_out < ours->winsize_out) { SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n"); new->winsize_out = theirs.winsize_out; } } return len; } /* * Limit values of certain facilities according to the capability of the * currently attached x25 link. */ void x25_limit_facilities(struct x25_facilities *facilities, struct x25_neigh *nb) { if (!nb->extended) { if (facilities->winsize_in > 7) { printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n"); facilities->winsize_in = 7; } if (facilities->winsize_out > 7) { facilities->winsize_out = 7; printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n"); } } }
