xnu-792.21.3.tar.gz

[apple/xnu.git] / bsd / netinet6 / frag6.c

diff --git a/bsd/netinet6/frag6.c b/bsd/netinet6/frag6.c
index 01888c6cb85569afb005fe923839dbe6942325cf..a495a046486fa572cd4da1c9381989b49eb317fb 100644 (file)
--- a/bsd/netinet6/frag6.c
+++ b/bsd/netinet6/frag6.c
@@ -42,6 +42,7 @@
 #include <sys/kernel.h>
 #include <sys/syslog.h>
 #include <kern/queue.h>
+#include <kern/locks.h>
 
 #include <net/if.h>
 #include <net/route.h>
@@ -61,21 +62,23 @@
  */
 #define IN6_IFSTAT_STRICT
 
-static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *));
-static void frag6_deq __P((struct ip6asfrag *));
-static void frag6_insque __P((struct ip6q *, struct ip6q *));
-static void frag6_remque __P((struct ip6q *));
-static void frag6_freef __P((struct ip6q *));
+static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *);
+static void frag6_deq(struct ip6asfrag *);
+static void frag6_insque(struct ip6q *, struct ip6q *);
+static void frag6_remque(struct ip6q *);
+static void frag6_freef(struct ip6q *);
 
 /* XXX we eventually need splreass6, or some real semaphore */
 int frag6_doing_reass;
 u_int frag6_nfragpackets;
+static u_int frag6_nfrags;
 struct ip6q ip6q;      /* ip6 reassemble queue */
 
 #ifndef __APPLE__
 MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header");
 #endif
 
+extern lck_mtx_t *inet6_domain_mutex;
 /*
  * Initialise reassembly queue and fragment identifier.
  */
@@ -84,7 +87,8 @@ frag6_init()
 {
        struct timeval tv;
 
-       ip6_maxfragpackets = nmbclusters / 4;
+       ip6_maxfragpackets = nmbclusters / 32;
+       ip6_maxfrags = nmbclusters / 4;
 
        /*
         * in many cases, random() here does NOT return random number
@@ -126,6 +130,8 @@ frag6_init()
  */
 /*
  * Fragment input
+ * NOTE: this function is called with the inet6_domain_mutex held from ip6_input.
+ *      inet6_domain_mutex is protecting he frag6 queue manipulation.
  */
 int
 frag6_input(mp, offp)
@@ -148,7 +154,7 @@ frag6_input(mp, offp)
 
        ip6 = mtod(m, struct ip6_hdr *);
 #ifndef PULLDOWN_TEST
-       IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
+       IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), return IPPROTO_DONE);
        ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset);
 #else
        IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
@@ -211,6 +217,16 @@ frag6_input(mp, offp)
 
        frag6_doing_reass = 1;
 
+       /*
+        * Enforce upper bound on number of fragments.
+        * If maxfrag is 0, never accept fragments.
+        * If maxfrag is -1, accept all fragments without limitation.
+        */
+       if (ip6_maxfrags < 0)
+               ;
+       else if (frag6_nfrags >= (u_int)ip6_maxfrags)
+               goto dropfrag;
+
        for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
                if (ip6f->ip6f_ident == q6->ip6q_ident &&
                    IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
@@ -253,6 +269,8 @@ frag6_input(mp, offp)
                q6->ip6q_src    = ip6->ip6_src;
                q6->ip6q_dst    = ip6->ip6_dst;
                q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
+
+               q6->ip6q_nfrag  = 0;
        }
 
        /*
@@ -431,6 +449,8 @@ insert:
         * the most recently active fragmented packet.
         */
        frag6_enq(ip6af, af6->ip6af_up);
+       frag6_nfrags++;
+       q6->ip6q_nfrag++;
 #if 0 /* xxx */
        if (q6 != ip6q.ip6q_next) {
                frag6_remque(q6);
@@ -493,6 +513,7 @@ insert:
                /* this comes with no copy if the boundary is on cluster */
                if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
                        frag6_remque(q6);
+                       frag6_nfrags -= q6->ip6q_nfrag;
                        FREE(q6, M_FTABLE);
                        frag6_nfragpackets--;
                        goto dropfrag;
@@ -510,6 +531,7 @@ insert:
        }
 
        frag6_remque(q6);
+       frag6_nfrags -= q6->ip6q_nfrag;
        FREE(q6, M_FTABLE);
        frag6_nfragpackets--;
 
@@ -571,7 +593,6 @@ frag6_freef(q6)
                        /* restoure source and destination addresses */
                        ip6->ip6_src = q6->ip6q_src;
                        ip6->ip6_dst = q6->ip6q_dst;
-
                        icmp6_error(m, ICMP6_TIME_EXCEEDED,
                                    ICMP6_TIME_EXCEED_REASSEMBLY, 0);
                } else
@@ -580,6 +601,7 @@ frag6_freef(q6)
 
        }
        frag6_remque(q6);
+       frag6_nfrags -= q6->ip6q_nfrag;
        FREE(q6, M_FTABLE);
        frag6_nfragpackets--;
 }
@@ -636,7 +658,7 @@ void
 frag6_slowtimo()
 {
        struct ip6q *q6;
-       int s = splnet();
+       lck_mtx_lock(inet6_domain_mutex);
 
        frag6_doing_reass = 1;
        q6 = ip6q.ip6q_next;
@@ -679,7 +701,7 @@ frag6_slowtimo()
        }
 #endif
 
-       splx(s);
+       lck_mtx_unlock(inet6_domain_mutex);
 }
 
 /*
@@ -690,9 +712,11 @@ frag6_drain()
 {
        if (frag6_doing_reass)
                return;
+       lck_mtx_lock(inet6_domain_mutex);
        while (ip6q.ip6q_next != &ip6q) {
                ip6stat.ip6s_fragdropped++;
                /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
                frag6_freef(ip6q.ip6q_next);
        }
+       lck_mtx_unlock(inet6_domain_mutex);
 }