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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 | * | |
315951e8 | 12 | * @(#)hd_output.c 7.6 (Berkeley) %G% |
21e3a7bd | 13 | */ |
edc74019 | 14 | |
4507dea2 KS |
15 | #include "param.h" |
16 | #include "systm.h" | |
17 | #include "mbuf.h" | |
18 | #include "domain.h" | |
19 | #include "socket.h" | |
42963956 | 20 | #include "syslog.h" |
4507dea2 KS |
21 | #include "protosw.h" |
22 | #include "errno.h" | |
23 | #include "time.h" | |
24 | #include "kernel.h" | |
25 | ||
edc74019 KS |
26 | #include "../net/if.h" |
27 | ||
4507dea2 KS |
28 | #include "hdlc.h" |
29 | #include "hd_var.h" | |
30 | #include "x25.h" | |
edc74019 KS |
31 | |
32 | /* | |
33 | * HDLC OUTPUT INTERFACE | |
34 | * | |
35 | * This routine is called when the X.25 packet layer output routine | |
36 | * has a information frame (iframe) to write. It is also called | |
37 | * by the input and control routines of the HDLC layer. | |
38 | */ | |
39 | ||
42963956 KS |
40 | hd_output (hdp, m0) |
41 | register struct hdcb *hdp; | |
42 | struct mbuf *m0; | |
edc74019 | 43 | { |
b84e7ca8 | 44 | struct x25config *xcp; |
42963956 KS |
45 | register struct mbuf *m = m0; |
46 | int len; | |
edc74019 KS |
47 | |
48 | if (m == NULL) | |
49 | panic ("hd_output"); | |
42963956 KS |
50 | if (m->m_flags & M_PKTHDR == 0) |
51 | panic ("hd_output 2"); | |
edc74019 | 52 | |
edc74019 KS |
53 | if (hdp->hd_state != ABM) { |
54 | m_freem (m); | |
55 | return; | |
56 | } | |
57 | ||
58 | /* | |
59 | * Make room for the hdlc header either by prepending | |
60 | * another mbuf, or by adjusting the offset and length | |
61 | * of the first mbuf in the mbuf chain. | |
62 | */ | |
63 | ||
42963956 | 64 | M_PREPEND(m, HDHEADERLN, M_DONTWAIT); |
b84e7ca8 KS |
65 | if (m == NULL) |
66 | return; | |
42963956 KS |
67 | for (len = 0; m; m = m->m_next) |
68 | len += m->m_len; | |
69 | m = m0; | |
70 | m->m_pkthdr.len = len; | |
edc74019 KS |
71 | |
72 | hd_append (&hdp->hd_txq, m); | |
73 | hd_start (hdp); | |
74 | } | |
75 | ||
76 | hd_start (hdp) | |
77 | register struct hdcb *hdp; | |
78 | { | |
79 | register struct mbuf *m; | |
80 | ||
81 | /* | |
82 | * The iframe is only transmitted if all these conditions are FALSE. | |
83 | * The iframe remains queued (hdp->hd_txq) however and will be | |
84 | * transmitted as soon as these conditions are cleared. | |
85 | */ | |
86 | ||
87 | while (!(hdp->hd_condition & (TIMER_RECOVERY_CONDITION | REMOTE_RNR_CONDITION | REJ_CONDITION))) { | |
88 | if (hdp->hd_vs == (hdp->hd_lastrxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) { | |
89 | ||
90 | /* We have now exceeded the maximum number of | |
91 | outstanding iframes. Therefore, we must wait | |
92 | until at least one is acknowledged if this | |
93 | condition is not turned off before we are | |
94 | requested to write another iframe. */ | |
95 | hdp->hd_window_condition++; | |
96 | break; | |
97 | } | |
98 | ||
99 | /* hd_remove top iframe from transmit queue. */ | |
100 | if ((m = hd_remove (&hdp->hd_txq)) == NULL) | |
101 | break; | |
102 | ||
103 | hd_send_iframe (hdp, m, POLLOFF); | |
104 | } | |
105 | } | |
106 | ||
107 | /* | |
108 | * This procedure is passed a buffer descriptor for an iframe. It builds | |
109 | * the rest of the control part of the frame and then writes it out. It | |
110 | * also starts the acknowledgement timer and keeps the iframe in the | |
111 | * Retransmit queue (Retxq) just in case we have to do this again. | |
112 | * | |
113 | * Note: This routine is also called from hd_input.c when retransmission | |
114 | * of old frames is required. | |
115 | */ | |
116 | ||
117 | hd_send_iframe (hdp, buf, poll_bit) | |
118 | register struct hdcb *hdp; | |
119 | register struct mbuf *buf; | |
120 | int poll_bit; | |
121 | { | |
122 | register struct Hdlc_iframe *iframe; | |
edc74019 KS |
123 | struct mbuf *m; |
124 | ||
125 | KILL_TIMER (hdp); | |
126 | ||
127 | if (buf == 0) { | |
128 | printf ("hd_send_iframe: zero arg\n"); | |
129 | #ifdef HDLCDEBUG | |
130 | hd_status (hdp); | |
131 | hd_dumptrace (hdp); | |
132 | #endif | |
133 | hdp->hd_vs = (hdp->hd_vs + 7) % MODULUS; | |
134 | return; | |
135 | } | |
136 | iframe = mtod (buf, struct Hdlc_iframe *); | |
137 | ||
138 | iframe -> hdlc_0 = 0; | |
139 | iframe -> nr = hdp->hd_vr; | |
140 | iframe -> pf = poll_bit; | |
141 | iframe -> ns = hdp->hd_vs; | |
142 | iframe -> address = ADDRESS_B; | |
143 | hdp->hd_lasttxnr = hdp->hd_vr; | |
144 | hdp->hd_rrtimer = 0; | |
145 | ||
146 | if (hdp->hd_vs == hdp->hd_retxqi) { | |
147 | /* Check for retransmissions. */ | |
148 | /* Put iframe only once in the Retransmission queue. */ | |
149 | hdp->hd_retxq[hdp->hd_retxqi] = buf; | |
150 | hdp->hd_retxqi = (hdp->hd_retxqi + 1) % MODULUS; | |
151 | hdp->hd_iframes_out++; | |
152 | } | |
153 | ||
154 | hdp->hd_vs = (hdp->hd_vs + 1) % MODULUS; | |
155 | ||
156 | hd_trace (hdp, TX, (struct Hdlc_frame *)iframe); | |
157 | ||
158 | /* Write buffer on device. */ | |
159 | m = hdp->hd_dontcopy ? buf : m_copy(buf, 0, (int)M_COPYALL); | |
160 | if (m == 0) { | |
161 | printf("hdlc: out of mbufs\n"); | |
162 | return; | |
163 | } | |
b84e7ca8 | 164 | (*hdp->hd_output)(hdp, m); |
edc74019 KS |
165 | SET_TIMER (hdp); |
166 | } | |
167 | ||
b84e7ca8 | 168 | hd_ifoutput(hdp, m) |
b84e7ca8 | 169 | register struct mbuf *m; |
42963956 | 170 | register struct hdcb *hdp; |
b84e7ca8 KS |
171 | { |
172 | /* | |
173 | * Queue message on interface, and start output if interface | |
174 | * not yet active. | |
175 | */ | |
4507dea2 | 176 | register struct ifnet *ifp = hdp->hd_ifp; |
b84e7ca8 | 177 | int s = splimp(); |
42963956 | 178 | |
b84e7ca8 KS |
179 | if (IF_QFULL(&ifp->if_snd)) { |
180 | IF_DROP(&ifp->if_snd); | |
42963956 KS |
181 | /* printf("%s%d: HDLC says OK to send but queue full, may hang\n", |
182 | ifp->if_name, ifp->if_unit);*/ | |
b84e7ca8 KS |
183 | m_freem(m); |
184 | } else { | |
185 | IF_ENQUEUE(&ifp->if_snd, m); | |
186 | if ((ifp->if_flags & IFF_OACTIVE) == 0) | |
187 | (*ifp->if_start)(ifp); | |
188 | } | |
189 | splx(s); | |
190 | } | |
191 | ||
192 | ||
edc74019 KS |
193 | /* |
194 | * This routine gets control when the timer expires because we have not | |
195 | * received an acknowledgement for a iframe. | |
196 | */ | |
197 | ||
198 | hd_resend_iframe (hdp) | |
199 | register struct hdcb *hdp; | |
200 | { | |
201 | ||
202 | if (hdp->hd_retxcnt++ < hd_n2) { | |
203 | if (!(hdp->hd_condition & TIMER_RECOVERY_CONDITION)) { | |
204 | hdp->hd_xx = hdp->hd_vs; | |
205 | hdp->hd_condition |= TIMER_RECOVERY_CONDITION; | |
206 | } | |
207 | ||
208 | hdp->hd_vs = hdp->hd_lastrxnr; | |
209 | hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLON); | |
210 | } else { | |
211 | /* At this point we have not received a RR even after N2 | |
212 | retries - attempt to reset link. */ | |
213 | ||
214 | hd_initvars (hdp); | |
215 | hd_writeinternal (hdp, SABM, POLLOFF); | |
216 | hdp->hd_state = WAIT_UA; | |
217 | SET_TIMER (hdp); | |
218 | hd_message (hdp, "Timer recovery failed: link down"); | |
315951e8 | 219 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp); |
edc74019 KS |
220 | } |
221 | } |