diff options
| author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 | 
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 | 
| commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
| tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/lapb/lapb_subr.c | |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'net/lapb/lapb_subr.c')
| -rw-r--r-- | net/lapb/lapb_subr.c | 313 | 
1 files changed, 313 insertions, 0 deletions
| diff --git a/net/lapb/lapb_subr.c b/net/lapb/lapb_subr.c new file mode 100644 index 00000000000..5de05a0bc0f --- /dev/null +++ b/net/lapb/lapb_subr.c @@ -0,0 +1,313 @@ +/* + *	LAPB release 002 + * + *	This code REQUIRES 2.1.15 or higher/ NET3.038 + * + *	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 + *	LAPB 001	Jonathan Naylor	Started Coding + */ + +#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/skbuff.h> +#include <net/sock.h> +#include <asm/uaccess.h> +#include <asm/system.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <net/lapb.h> + +/* + *	This routine purges all the queues of frames. + */ +void lapb_clear_queues(struct lapb_cb *lapb) +{ +	skb_queue_purge(&lapb->write_queue); +	skb_queue_purge(&lapb->ack_queue); +} + +/* + * This routine purges the input queue of those frames that have been + * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the + * SDL diagram. + */ +void lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr) +{ +	struct sk_buff *skb; +	int modulus; + +	modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; + +	/* +	 * Remove all the ack-ed frames from the ack queue. +	 */ +	if (lapb->va != nr) +		while (skb_peek(&lapb->ack_queue) && lapb->va != nr) { +		        skb = skb_dequeue(&lapb->ack_queue); +			kfree_skb(skb); +			lapb->va = (lapb->va + 1) % modulus; +		} +} + +void lapb_requeue_frames(struct lapb_cb *lapb) +{ +        struct sk_buff *skb, *skb_prev = NULL; + +	/* +	 * Requeue all the un-ack-ed frames on the output queue to be picked +	 * up by lapb_kick called from the timer. This arrangement handles the +	 * possibility of an empty output queue. +	 */ +	while ((skb = skb_dequeue(&lapb->ack_queue)) != NULL) { +		if (!skb_prev) +			skb_queue_head(&lapb->write_queue, skb); +		else +			skb_append(skb_prev, skb); +		skb_prev = skb; +	} +} + +/* + *	Validate that the value of nr is between va and vs. Return true or + *	false for testing. + */ +int lapb_validate_nr(struct lapb_cb *lapb, unsigned short nr) +{ +	unsigned short vc = lapb->va; +	int modulus; +	 +	modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; + +	while (vc != lapb->vs) { +		if (nr == vc) +			return 1; +		vc = (vc + 1) % modulus; +	} +	 +	return nr == lapb->vs; +} + +/* + *	This routine is the centralised routine for parsing the control + *	information for the different frame formats. + */ +int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb, +		struct lapb_frame *frame) +{ +	frame->type = LAPB_ILLEGAL; + +#if LAPB_DEBUG > 2 +	printk(KERN_DEBUG "lapb: (%p) S%d RX %02X %02X %02X\n", +	       lapb->dev, lapb->state, +	       skb->data[0], skb->data[1], skb->data[2]); +#endif + +	/* We always need to look at 2 bytes, sometimes we need +	 * to look at 3 and those cases are handled below. +	 */ +	if (!pskb_may_pull(skb, 2)) +		return -1; + +	if (lapb->mode & LAPB_MLP) { +		if (lapb->mode & LAPB_DCE) { +			if (skb->data[0] == LAPB_ADDR_D) +				frame->cr = LAPB_COMMAND; +			if (skb->data[0] == LAPB_ADDR_C) +				frame->cr = LAPB_RESPONSE; +		} else { +			if (skb->data[0] == LAPB_ADDR_C) +				frame->cr = LAPB_COMMAND; +			if (skb->data[0] == LAPB_ADDR_D) +				frame->cr = LAPB_RESPONSE; +		} +	} else { +		if (lapb->mode & LAPB_DCE) { +			if (skb->data[0] == LAPB_ADDR_B) +				frame->cr = LAPB_COMMAND; +			if (skb->data[0] == LAPB_ADDR_A) +				frame->cr = LAPB_RESPONSE; +		} else { +			if (skb->data[0] == LAPB_ADDR_A) +				frame->cr = LAPB_COMMAND; +			if (skb->data[0] == LAPB_ADDR_B) +				frame->cr = LAPB_RESPONSE; +		} +	} +		 +	skb_pull(skb, 1); + +	if (lapb->mode & LAPB_EXTENDED) { +		if (!(skb->data[0] & LAPB_S)) { +			if (!pskb_may_pull(skb, 2)) +				return -1; +			/* +			 * I frame - carries NR/NS/PF +			 */ +			frame->type       = LAPB_I; +			frame->ns         = (skb->data[0] >> 1) & 0x7F; +			frame->nr         = (skb->data[1] >> 1) & 0x7F; +			frame->pf         = skb->data[1] & LAPB_EPF; +			frame->control[0] = skb->data[0]; +			frame->control[1] = skb->data[1]; +			skb_pull(skb, 2); +		} else if ((skb->data[0] & LAPB_U) == 1) { +			if (!pskb_may_pull(skb, 2)) +				return -1; +			/* +			 * S frame - take out PF/NR +			 */ +			frame->type       = skb->data[0] & 0x0F; +			frame->nr         = (skb->data[1] >> 1) & 0x7F; +			frame->pf         = skb->data[1] & LAPB_EPF; +			frame->control[0] = skb->data[0]; +			frame->control[1] = skb->data[1]; +			skb_pull(skb, 2); +		} else if ((skb->data[0] & LAPB_U) == 3) { +			/* +			 * U frame - take out PF +			 */ +			frame->type       = skb->data[0] & ~LAPB_SPF; +			frame->pf         = skb->data[0] & LAPB_SPF; +			frame->control[0] = skb->data[0]; +			frame->control[1] = 0x00; +			skb_pull(skb, 1); +		} +	} else { +		if (!(skb->data[0] & LAPB_S)) { +			/* +			 * I frame - carries NR/NS/PF +			 */ +			frame->type = LAPB_I; +			frame->ns   = (skb->data[0] >> 1) & 0x07; +			frame->nr   = (skb->data[0] >> 5) & 0x07; +			frame->pf   = skb->data[0] & LAPB_SPF; +		} else if ((skb->data[0] & LAPB_U) == 1) { +			/* +			 * S frame - take out PF/NR +			 */ +			frame->type = skb->data[0] & 0x0F; +			frame->nr   = (skb->data[0] >> 5) & 0x07; +			frame->pf   = skb->data[0] & LAPB_SPF; +		} else if ((skb->data[0] & LAPB_U) == 3) { +			/* +			 * U frame - take out PF +			 */ +			frame->type = skb->data[0] & ~LAPB_SPF; +			frame->pf   = skb->data[0] & LAPB_SPF; +		} + +		frame->control[0] = skb->data[0]; + +		skb_pull(skb, 1); +	} + +	return 0; +} + +/*  + *	This routine is called when the HDLC layer internally  generates a + *	command or  response  for  the remote machine ( eg. RR, UA etc. ).  + *	Only supervisory or unnumbered frames are processed, FRMRs are handled + *	by lapb_transmit_frmr below. + */ +void lapb_send_control(struct lapb_cb *lapb, int frametype, +		       int poll_bit, int type) +{ +	struct sk_buff *skb; +	unsigned char  *dptr; + +	if ((skb = alloc_skb(LAPB_HEADER_LEN + 3, GFP_ATOMIC)) == NULL) +		return; + +	skb_reserve(skb, LAPB_HEADER_LEN + 1); + +	if (lapb->mode & LAPB_EXTENDED) { +		if ((frametype & LAPB_U) == LAPB_U) { +			dptr   = skb_put(skb, 1); +			*dptr  = frametype; +			*dptr |= poll_bit ? LAPB_SPF : 0; +		} else { +			dptr     = skb_put(skb, 2); +			dptr[0]  = frametype; +			dptr[1]  = (lapb->vr << 1); +			dptr[1] |= poll_bit ? LAPB_EPF : 0; +		} +	} else { +		dptr   = skb_put(skb, 1); +		*dptr  = frametype; +		*dptr |= poll_bit ? LAPB_SPF : 0; +		if ((frametype & LAPB_U) == LAPB_S)	/* S frames carry NR */ +			*dptr |= (lapb->vr << 5); +	} + +	lapb_transmit_buffer(lapb, skb, type); +} + +/*  + *	This routine generates FRMRs based on information previously stored in + *	the LAPB control block. + */ +void lapb_transmit_frmr(struct lapb_cb *lapb) +{ +	struct sk_buff *skb; +	unsigned char  *dptr; + +	if ((skb = alloc_skb(LAPB_HEADER_LEN + 7, GFP_ATOMIC)) == NULL) +		return; + +	skb_reserve(skb, LAPB_HEADER_LEN + 1); + +	if (lapb->mode & LAPB_EXTENDED) { +		dptr    = skb_put(skb, 6); +		*dptr++ = LAPB_FRMR; +		*dptr++ = lapb->frmr_data.control[0]; +		*dptr++ = lapb->frmr_data.control[1]; +		*dptr++ = (lapb->vs << 1) & 0xFE; +		*dptr   = (lapb->vr << 1) & 0xFE; +		if (lapb->frmr_data.cr == LAPB_RESPONSE) +			*dptr |= 0x01; +		dptr++; +		*dptr++ = lapb->frmr_type; + +#if LAPB_DEBUG > 1 +	printk(KERN_DEBUG "lapb: (%p) S%d TX FRMR %02X %02X %02X %02X %02X\n", +	       lapb->dev, lapb->state, +	       skb->data[1], skb->data[2], skb->data[3], +	       skb->data[4], skb->data[5]); +#endif +	} else { +		dptr    = skb_put(skb, 4); +		*dptr++ = LAPB_FRMR; +		*dptr++ = lapb->frmr_data.control[0]; +		*dptr   = (lapb->vs << 1) & 0x0E; +		*dptr  |= (lapb->vr << 5) & 0xE0; +		if (lapb->frmr_data.cr == LAPB_RESPONSE) +			*dptr |= 0x10; +		dptr++; +		*dptr++ = lapb->frmr_type; + +#if LAPB_DEBUG > 1 +	printk(KERN_DEBUG "lapb: (%p) S%d TX FRMR %02X %02X %02X\n", +	       lapb->dev, lapb->state, skb->data[1], +	       skb->data[2], skb->data[3]); +#endif +	} + +	lapb_transmit_buffer(lapb, skb, LAPB_RESPONSE); +} | 
