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21e3a7bd KS |
1 | /* |
2 | * Copyright (c) University of British Columbia, 1984 | |
3 | * Copyright (c) 1990 The Regents of the University of California. | |
4 | * All rights reserved. | |
5 | * | |
6 | * This code is derived from software contributed to Berkeley by | |
7 | * the Laboratory for Computation Vision and the Computer Science Department | |
8 | * of the University of British Columbia. | |
9 | * | |
10 | * %sccs.include.redist.c% | |
11 | * | |
b84e7ca8 | 12 | * @(#)hd_output.c 7.3 (Berkeley) %G% |
21e3a7bd | 13 | */ |
edc74019 KS |
14 | |
15 | #include "../h/param.h" | |
16 | #include "../h/systm.h" | |
17 | #include "../h/mbuf.h" | |
18 | #include "../h/domain.h" | |
19 | #include "../h/socket.h" | |
20 | #include "../h/protosw.h" | |
21 | #include "../h/errno.h" | |
22 | #include "../h/time.h" | |
23 | #include "../h/kernel.h" | |
24 | #include "../net/if.h" | |
25 | ||
26 | #include "../netccitt/hdlc.h" | |
27 | #include "../netccitt/hd_var.h" | |
28 | #include "../netccitt/x25.h" | |
29 | ||
30 | /* | |
31 | * HDLC OUTPUT INTERFACE | |
32 | * | |
33 | * This routine is called when the X.25 packet layer output routine | |
34 | * has a information frame (iframe) to write. It is also called | |
35 | * by the input and control routines of the HDLC layer. | |
36 | */ | |
37 | ||
b84e7ca8 | 38 | hd_output (m, info) |
edc74019 | 39 | register struct mbuf *m; |
b84e7ca8 | 40 | caddr_t info; |
edc74019 | 41 | { |
b84e7ca8 KS |
42 | register struct hdcb *hdp = (struct hdcb *)info; |
43 | struct x25config *xcp; | |
edc74019 KS |
44 | |
45 | if (m == NULL) | |
46 | panic ("hd_output"); | |
47 | ||
edc74019 KS |
48 | if (hdp->hd_state != ABM) { |
49 | m_freem (m); | |
50 | return; | |
51 | } | |
52 | ||
53 | /* | |
54 | * Make room for the hdlc header either by prepending | |
55 | * another mbuf, or by adjusting the offset and length | |
56 | * of the first mbuf in the mbuf chain. | |
57 | */ | |
58 | ||
b84e7ca8 KS |
59 | M_PREPEND(m, M_DONTWAIT, HDHEADERLN); |
60 | if (m == NULL) | |
61 | return; | |
edc74019 KS |
62 | |
63 | hd_append (&hdp->hd_txq, m); | |
64 | hd_start (hdp); | |
65 | } | |
66 | ||
67 | hd_start (hdp) | |
68 | register struct hdcb *hdp; | |
69 | { | |
70 | register struct mbuf *m; | |
71 | ||
72 | /* | |
73 | * The iframe is only transmitted if all these conditions are FALSE. | |
74 | * The iframe remains queued (hdp->hd_txq) however and will be | |
75 | * transmitted as soon as these conditions are cleared. | |
76 | */ | |
77 | ||
78 | while (!(hdp->hd_condition & (TIMER_RECOVERY_CONDITION | REMOTE_RNR_CONDITION | REJ_CONDITION))) { | |
79 | if (hdp->hd_vs == (hdp->hd_lastrxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) { | |
80 | ||
81 | /* We have now exceeded the maximum number of | |
82 | outstanding iframes. Therefore, we must wait | |
83 | until at least one is acknowledged if this | |
84 | condition is not turned off before we are | |
85 | requested to write another iframe. */ | |
86 | hdp->hd_window_condition++; | |
87 | break; | |
88 | } | |
89 | ||
90 | /* hd_remove top iframe from transmit queue. */ | |
91 | if ((m = hd_remove (&hdp->hd_txq)) == NULL) | |
92 | break; | |
93 | ||
94 | hd_send_iframe (hdp, m, POLLOFF); | |
95 | } | |
96 | } | |
97 | ||
98 | /* | |
99 | * This procedure is passed a buffer descriptor for an iframe. It builds | |
100 | * the rest of the control part of the frame and then writes it out. It | |
101 | * also starts the acknowledgement timer and keeps the iframe in the | |
102 | * Retransmit queue (Retxq) just in case we have to do this again. | |
103 | * | |
104 | * Note: This routine is also called from hd_input.c when retransmission | |
105 | * of old frames is required. | |
106 | */ | |
107 | ||
108 | hd_send_iframe (hdp, buf, poll_bit) | |
109 | register struct hdcb *hdp; | |
110 | register struct mbuf *buf; | |
111 | int poll_bit; | |
112 | { | |
113 | register struct Hdlc_iframe *iframe; | |
edc74019 | 114 | struct mbuf *m; |
b84e7ca8 | 115 | int s |
edc74019 KS |
116 | |
117 | KILL_TIMER (hdp); | |
118 | ||
119 | if (buf == 0) { | |
120 | printf ("hd_send_iframe: zero arg\n"); | |
121 | #ifdef HDLCDEBUG | |
122 | hd_status (hdp); | |
123 | hd_dumptrace (hdp); | |
124 | #endif | |
125 | hdp->hd_vs = (hdp->hd_vs + 7) % MODULUS; | |
126 | return; | |
127 | } | |
128 | iframe = mtod (buf, struct Hdlc_iframe *); | |
129 | ||
130 | iframe -> hdlc_0 = 0; | |
131 | iframe -> nr = hdp->hd_vr; | |
132 | iframe -> pf = poll_bit; | |
133 | iframe -> ns = hdp->hd_vs; | |
134 | iframe -> address = ADDRESS_B; | |
135 | hdp->hd_lasttxnr = hdp->hd_vr; | |
136 | hdp->hd_rrtimer = 0; | |
137 | ||
138 | if (hdp->hd_vs == hdp->hd_retxqi) { | |
139 | /* Check for retransmissions. */ | |
140 | /* Put iframe only once in the Retransmission queue. */ | |
141 | hdp->hd_retxq[hdp->hd_retxqi] = buf; | |
142 | hdp->hd_retxqi = (hdp->hd_retxqi + 1) % MODULUS; | |
143 | hdp->hd_iframes_out++; | |
144 | } | |
145 | ||
146 | hdp->hd_vs = (hdp->hd_vs + 1) % MODULUS; | |
147 | ||
148 | hd_trace (hdp, TX, (struct Hdlc_frame *)iframe); | |
149 | ||
150 | /* Write buffer on device. */ | |
151 | m = hdp->hd_dontcopy ? buf : m_copy(buf, 0, (int)M_COPYALL); | |
152 | if (m == 0) { | |
153 | printf("hdlc: out of mbufs\n"); | |
154 | return; | |
155 | } | |
b84e7ca8 | 156 | (*hdp->hd_output)(hdp, m); |
edc74019 KS |
157 | SET_TIMER (hdp); |
158 | } | |
159 | ||
b84e7ca8 KS |
160 | hd_ifoutput(hdp, m) |
161 | register struct hdcb *hdp; | |
162 | register struct mbuf *m; | |
163 | { | |
164 | /* | |
165 | * Queue message on interface, and start output if interface | |
166 | * not yet active. | |
167 | */ | |
168 | register struct ifnet *ifp = hdp->hdp_ifp; | |
169 | int s = splimp(); | |
170 | if (IF_QFULL(&ifp->if_snd)) { | |
171 | IF_DROP(&ifp->if_snd); | |
172 | printf("%s%d: HDLC says OK to send but queue full, may hang\n", | |
173 | ifp->if_name, ifp->if_unit); | |
174 | m_freem(m); | |
175 | } else { | |
176 | IF_ENQUEUE(&ifp->if_snd, m); | |
177 | if ((ifp->if_flags & IFF_OACTIVE) == 0) | |
178 | (*ifp->if_start)(ifp); | |
179 | } | |
180 | splx(s); | |
181 | } | |
182 | ||
183 | ||
edc74019 KS |
184 | /* |
185 | * This routine gets control when the timer expires because we have not | |
186 | * received an acknowledgement for a iframe. | |
187 | */ | |
188 | ||
189 | hd_resend_iframe (hdp) | |
190 | register struct hdcb *hdp; | |
191 | { | |
192 | ||
193 | if (hdp->hd_retxcnt++ < hd_n2) { | |
194 | if (!(hdp->hd_condition & TIMER_RECOVERY_CONDITION)) { | |
195 | hdp->hd_xx = hdp->hd_vs; | |
196 | hdp->hd_condition |= TIMER_RECOVERY_CONDITION; | |
197 | } | |
198 | ||
199 | hdp->hd_vs = hdp->hd_lastrxnr; | |
200 | hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLON); | |
201 | } else { | |
202 | /* At this point we have not received a RR even after N2 | |
203 | retries - attempt to reset link. */ | |
204 | ||
205 | hd_initvars (hdp); | |
206 | hd_writeinternal (hdp, SABM, POLLOFF); | |
207 | hdp->hd_state = WAIT_UA; | |
208 | SET_TIMER (hdp); | |
209 | hd_message (hdp, "Timer recovery failed: link down"); | |
210 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_xcp); | |
211 | } | |
212 | } |