From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- net/x25/x25_facilities.c | 354 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 354 insertions(+) create mode 100644 net/x25/x25_facilities.c (limited to 'net/x25/x25_facilities.c') diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c new file mode 100644 index 000000000..7ecd04c21 --- /dev/null +++ b/net/x25/x25_facilities.c @@ -0,0 +1,354 @@ +/* + * 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. + */ + +#define pr_fmt(fmt) "X25: " fmt + +#include +#include +#include +#include +#include + +/** + * x25_parse_facilities - Parse facilities from skb into the facilities structs + * + * @skb: sk_buff to parse + * @facilities: Regular facilities, updated as facilities are found + * @dte_facs: ITU DTE facilities, updated as DTE facilities are found + * @vc_fac_mask: mask is updated with all facilities found + * + * Return codes: + * -1 - Parsing error, caller should drop call and clean up + * 0 - Parse OK, this skb has no facilities + * >0 - Parse OK, returns the length of the facilities header + * + */ +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; + unsigned int len; + + *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)); + + if (!pskb_may_pull(skb, 1)) + return 0; + + len = skb->data[0]; + + if (!pskb_may_pull(skb, 1 + len)) + return -1; + + p = skb->data + 1; + + while (len > 0) { + switch (*p & X25_FAC_CLASS_MASK) { + case X25_FAC_CLASS_A: + if (len < 2) + return -1; + 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: + pr_debug("unknown facility " + "%02X, value %02X\n", + p[0], p[1]); + break; + } + p += 2; + len -= 2; + break; + case X25_FAC_CLASS_B: + if (len < 3) + return -1; + 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: + pr_debug("unknown facility " + "%02X, values %02X, %02X\n", + p[0], p[1], p[2]); + break; + } + p += 3; + len -= 3; + break; + case X25_FAC_CLASS_C: + if (len < 4) + return -1; + pr_debug("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: + if (len < p[1] + 2) + return -1; + switch (*p) { + case X25_FAC_CALLING_AE: + if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1) + return -1; + if (p[2] > X25_MAX_AE_LEN) + return -1; + 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 || p[1] <= 1) + return -1; + if (p[2] > X25_MAX_AE_LEN) + return -1; + 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: + pr_debug("unknown facility %02X," + "length %d\n", p[0], p[1]); + 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 int bytecount = (dte_facs->calling_len + 1) >> 1; + *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 int 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); + if (len < 0) + return len; + + /* + * 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) { + int theirs_in = theirs.throughput & 0x0f; + int theirs_out = theirs.throughput & 0xf0; + int ours_in = ours->throughput & 0x0f; + int ours_out = ours->throughput & 0xf0; + if (!ours_in || theirs_in < ours_in) { + SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n"); + new->throughput = (new->throughput & 0xf0) | theirs_in; + } + if (!ours_out || theirs_out < ours_out) { + SOCK_DEBUG(sk, + "X.25: outbound throughput negotiated\n"); + new->throughput = (new->throughput & 0x0f) | theirs_out; + } + } + + 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) { + pr_debug("incoming winsize limited to 7\n"); + facilities->winsize_in = 7; + } + if (facilities->winsize_out > 7) { + facilities->winsize_out = 7; + pr_debug("outgoing winsize limited to 7\n"); + } + } +} -- cgit v1.2.3-54-g00ecf