From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-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! --- net/lapb/lapb_subr.c | 313 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 313 insertions(+) create mode 100644 net/lapb/lapb_subr.c (limited to 'net/lapb/lapb_subr.c') 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * 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); +} -- cgit v1.2.3