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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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29 * @(#)tcp_input.c 8.12 (Berkeley) 5/24/95
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
36 #include "opt_inet6.h"
37 #include "opt_tcpdebug.h"
39 #include <sys/param.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
43 #include <sys/socket.h>
44 #include <sys/socketvar.h>
45 #include <sys/sysctl.h>
46 #include <sys/syslog.h>
47 #include <sys/systm.h>
52 #include <net/route.h>
55 #include <netinet/in.h>
56 #include <netinet/in_pcb.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/in_var.h>
59 #include <netinet/ip.h>
60 #include <netinet/ip_var.h>
61 #include <netinet/ip_options.h>
62 #include <netinet/ip6.h>
63 #include <netinet6/in6_pcb.h>
64 #include <netinet6/ip6_var.h>
65 #include <netinet6/nd6.h>
66 #include <netinet/tcp.h>
67 #include <netinet/tcp_fsm.h>
68 #include <netinet/tcp_seq.h>
69 #include <netinet/tcp_timer.h>
70 #include <netinet/tcp_var.h>
71 #include <netinet6/tcp6_var.h>
72 #include <netinet/tcpip.h>
74 #include <netinet/tcp_debug.h>
77 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW, 0,
78 "TCP Segment Reassembly Queue");
80 static VNET_DEFINE(int, tcp_reass_maxseg) = 0;
81 #define V_tcp_reass_maxseg VNET(tcp_reass_maxseg)
82 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RDTUN,
83 &VNET_NAME(tcp_reass_maxseg), 0,
84 "Global maximum number of TCP Segments in Reassembly Queue");
86 VNET_DEFINE(int, tcp_reass_qsize) = 0;
87 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, cursegments, CTLFLAG_RD,
88 &VNET_NAME(tcp_reass_qsize), 0,
89 "Global number of TCP Segments currently in Reassembly Queue");
91 static VNET_DEFINE(int, tcp_reass_maxqlen) = 48;
92 #define V_tcp_reass_maxqlen VNET(tcp_reass_maxqlen)
93 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, maxqlen, CTLFLAG_RW,
94 &VNET_NAME(tcp_reass_maxqlen), 0,
95 "Maximum number of TCP Segments per individual Reassembly Queue");
97 static VNET_DEFINE(int, tcp_reass_overflows) = 0;
98 #define V_tcp_reass_overflows VNET(tcp_reass_overflows)
99 SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, overflows, CTLFLAG_RD,
100 &VNET_NAME(tcp_reass_overflows), 0,
101 "Global number of TCP Segment Reassembly Queue Overflows");
103 /* Initialize TCP reassembly queue */
105 tcp_reass_zone_change(void *tag)
108 V_tcp_reass_maxseg = nmbclusters / 16;
109 uma_zone_set_max(V_tcp_reass_zone, V_tcp_reass_maxseg);
112 VNET_DEFINE(uma_zone_t, tcp_reass_zone);
118 V_tcp_reass_maxseg = nmbclusters / 16;
119 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments",
120 &V_tcp_reass_maxseg);
121 V_tcp_reass_zone = uma_zcreate("tcpreass", sizeof (struct tseg_qent),
122 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
123 uma_zone_set_max(V_tcp_reass_zone, V_tcp_reass_maxseg);
124 EVENTHANDLER_REGISTER(nmbclusters_change,
125 tcp_reass_zone_change, NULL, EVENTHANDLER_PRI_ANY);
130 tcp_reass_destroy(void)
133 uma_zdestroy(V_tcp_reass_zone);
138 tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m)
141 struct tseg_qent *p = NULL;
142 struct tseg_qent *nq;
143 struct tseg_qent *te = NULL;
144 struct socket *so = tp->t_inpcb->inp_socket;
147 INP_WLOCK_ASSERT(tp->t_inpcb);
150 * XXX: tcp_reass() is rather inefficient with its data structures
151 * and should be rewritten (see NetBSD for optimizations).
155 * Call with th==NULL after become established to
156 * force pre-ESTABLISHED data up to user socket.
162 * Limit the number of segments in the reassembly queue to prevent
163 * holding on to too many segments (and thus running out of mbufs).
164 * Make sure to let the missing segment through which caused this
165 * queue. Always keep one global queue entry spare to be able to
166 * process the missing segment.
168 if (th->th_seq != tp->rcv_nxt &&
169 (V_tcp_reass_qsize + 1 >= V_tcp_reass_maxseg ||
170 tp->t_segqlen >= V_tcp_reass_maxqlen)) {
171 V_tcp_reass_overflows++;
172 TCPSTAT_INC(tcps_rcvmemdrop);
179 * Allocate a new queue entry. If we can't, or hit the zone limit
182 te = uma_zalloc(V_tcp_reass_zone, M_NOWAIT);
184 TCPSTAT_INC(tcps_rcvmemdrop);
193 * Find a segment which begins after this one does.
195 LIST_FOREACH(q, &tp->t_segq, tqe_q) {
196 if (SEQ_GT(q->tqe_th->th_seq, th->th_seq))
202 * If there is a preceding segment, it may provide some of
203 * our data already. If so, drop the data from the incoming
204 * segment. If it provides all of our data, drop us.
208 /* conversion to int (in i) handles seq wraparound */
209 i = p->tqe_th->th_seq + p->tqe_len - th->th_seq;
212 TCPSTAT_INC(tcps_rcvduppack);
213 TCPSTAT_ADD(tcps_rcvdupbyte, *tlenp);
215 uma_zfree(V_tcp_reass_zone, te);
219 * Try to present any queued data
220 * at the left window edge to the user.
221 * This is needed after the 3-WHS
224 goto present; /* ??? */
231 TCPSTAT_INC(tcps_rcvoopack);
232 TCPSTAT_ADD(tcps_rcvoobyte, *tlenp);
235 * While we overlap succeeding segments trim them or,
236 * if they are completely covered, dequeue them.
239 int i = (th->th_seq + *tlenp) - q->tqe_th->th_seq;
242 if (i < q->tqe_len) {
243 q->tqe_th->th_seq += i;
249 nq = LIST_NEXT(q, tqe_q);
250 LIST_REMOVE(q, tqe_q);
252 uma_zfree(V_tcp_reass_zone, q);
258 /* Insert the new segment queue entry into place. */
261 te->tqe_len = *tlenp;
264 LIST_INSERT_HEAD(&tp->t_segq, te, tqe_q);
266 LIST_INSERT_AFTER(p, te, tqe_q);
271 * Present data to user, advancing rcv_nxt through
272 * completed sequence space.
274 if (!TCPS_HAVEESTABLISHED(tp->t_state))
276 q = LIST_FIRST(&tp->t_segq);
277 if (!q || q->tqe_th->th_seq != tp->rcv_nxt)
279 SOCKBUF_LOCK(&so->so_rcv);
281 tp->rcv_nxt += q->tqe_len;
282 flags = q->tqe_th->th_flags & TH_FIN;
283 nq = LIST_NEXT(q, tqe_q);
284 LIST_REMOVE(q, tqe_q);
285 if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
288 sbappendstream_locked(&so->so_rcv, q->tqe_m);
289 uma_zfree(V_tcp_reass_zone, q);
293 } while (q && q->tqe_th->th_seq == tp->rcv_nxt);
295 sorwakeup_locked(so);