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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 | // SPDX-License-Identifier: GPL-2.0-or-later /* * LAPB release 002 * * This code REQUIRES 2.1.15 or higher/ NET3.038 * * History * LAPB 001 Jonathan Naylor Started Coding * LAPB 002 Jonathan Naylor New timer architecture. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/errno.h> #include <linux/types.h> #include <linux/socket.h> #include <linux/in.h> #include <linux/kernel.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 <linux/slab.h> #include <net/sock.h> #include <linux/uaccess.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <net/lapb.h> /* * This procedure is passed a buffer descriptor for an iframe. It builds * the rest of the control part of the frame and then writes it out. */ static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) { unsigned char *frame; if (!skb) return; if (lapb->mode & LAPB_EXTENDED) { frame = skb_push(skb, 2); frame[0] = LAPB_I; frame[0] |= lapb->vs << 1; frame[1] = poll_bit ? LAPB_EPF : 0; frame[1] |= lapb->vr << 1; } else { frame = skb_push(skb, 1); *frame = LAPB_I; *frame |= poll_bit ? LAPB_SPF : 0; *frame |= lapb->vr << 5; *frame |= lapb->vs << 1; } lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n", lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); } void lapb_kick(struct lapb_cb *lapb) { struct sk_buff *skb, *skbn; unsigned short modulus, start, end; modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; end = (lapb->va + lapb->window) % modulus; if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && start != end && skb_peek(&lapb->write_queue)) { lapb->vs = start; /* * Dequeue the frame and copy it. */ skb = skb_dequeue(&lapb->write_queue); do { skbn = skb_copy(skb, GFP_ATOMIC); if (!skbn) { skb_queue_head(&lapb->write_queue, skb); break; } if (skb->sk) skb_set_owner_w(skbn, skb->sk); /* * Transmit the frame copy. */ lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); lapb->vs = (lapb->vs + 1) % modulus; /* * Requeue the original data frame. */ skb_queue_tail(&lapb->ack_queue, skb); } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; if (!lapb_t1timer_running(lapb)) lapb_start_t1timer(lapb); } } void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) { unsigned char *ptr; ptr = skb_push(skb, 1); if (lapb->mode & LAPB_MLP) { if (lapb->mode & LAPB_DCE) { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_C; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_D; } else { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_D; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_C; } } else { if (lapb->mode & LAPB_DCE) { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_A; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_B; } else { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_B; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_A; } } lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data); if (!lapb_data_transmit(lapb, skb)) kfree_skb(skb); } void lapb_establish_data_link(struct lapb_cb *lapb) { lapb->condition = 0x00; lapb->n2count = 0; if (lapb->mode & LAPB_EXTENDED) { lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state); lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); } else { lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state); lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); } lapb_start_t1timer(lapb); lapb_stop_t2timer(lapb); } void lapb_enquiry_response(struct lapb_cb *lapb) { lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n", lapb->dev, lapb->state, lapb->vr); lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; } void lapb_timeout_response(struct lapb_cb *lapb) { lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n", lapb->dev, lapb->state, lapb->vr); lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; } void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) { if (lapb->vs == nr) { lapb_frames_acked(lapb, nr); lapb_stop_t1timer(lapb); lapb->n2count = 0; } else if (lapb->va != nr) { lapb_frames_acked(lapb, nr); lapb_start_t1timer(lapb); } } void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) { if (type == LAPB_COMMAND && pf) lapb_enquiry_response(lapb); } |