xnu-4570.51.1.tar.gz

[apple/xnu.git] / bsd / kern / uipc_mbuf2.c

diff --git a/bsd/kern/uipc_mbuf2.c b/bsd/kern/uipc_mbuf2.c
index a56ffa99077d5132b03ce78cd37ff420e80fcf51..31edbc0ce026a480c5d2dee9a3042caf0cc5a19b 100644 (file)
--- a/bsd/kern/uipc_mbuf2.c
+++ b/bsd/kern/uipc_mbuf2.c
@@ -1,5 +1,5 @@
 /*
 /*

- * Copyright (c) 2000-2013 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2018 Apple Inc. All rights reserved.

  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 


@@ -130,9 +130,9 @@
 struct mbuf *
 m_pulldown(struct mbuf *m, int off, int len, int *offp)
 {
 struct mbuf *
 m_pulldown(struct mbuf *m, int off, int len, int *offp)
 {

-       struct mbuf *n, *o;
-       int hlen, tlen, olen;
-       int sharedcluster;
+       struct mbuf *n = NULL, *o = NULL;
+       int hlen = 0, tlen = 0, olen = 0;
+       int sharedcluster = 0;

 #if defined(PULLDOWN_STAT) && INET6
        static struct mbuf *prev = NULL;
        int prevlen = 0, prevmlen = 0;
 #if defined(PULLDOWN_STAT) && INET6
        static struct mbuf *prev = NULL;
        int prevlen = 0, prevmlen = 0;


@@ -222,15 +222,24 @@ m_pulldown(struct mbuf *m, int off, int len, int *offp)
     }
 #endif
        n = m;
     }
 #endif
        n = m;

+
+       /*
+        * Iterate and make n point to the mbuf
+        * within which the first byte at length
+        * offset is contained from the start of
+        * mbuf chain.
+        */

        while (n != NULL && off > 0) {
                if (n->m_len > off)
                        break;
                off -= n->m_len;
                n = n->m_next;
        }
        while (n != NULL && off > 0) {
                if (n->m_len > off)
                        break;
                off -= n->m_len;
                n = n->m_next;
        }

+

        /* be sure to point non-empty mbuf */
        while (n != NULL && n->m_len == 0)
                n = n->m_next;
        /* be sure to point non-empty mbuf */
        while (n != NULL && n->m_len == 0)
                n = n->m_next;

+

        if (!n) {
                m_freem(m);
                return NULL;    /* mbuf chain too short */
        if (!n) {
                m_freem(m);
                return NULL;    /* mbuf chain too short */


@@ -239,6 +248,16 @@ m_pulldown(struct mbuf *m, int off, int len, int *offp)
        /*
         * the target data is on <n, off>.
         * if we got enough data on the mbuf "n", we're done.
        /*
         * the target data is on <n, off>.
         * if we got enough data on the mbuf "n", we're done.

+        *
+        * It should be noted, that we should only do this either
+        * when offset is 0, i.e. data is pointing to the start
+        * or when the caller specifies an out argument to get
+        * the offset value in the mbuf to work with data pointer
+        * correctly.
+        *
+        * If offset is not 0 and caller did not provide out-argument
+        * to get offset, we should split the mbuf even when the length
+        * is contained in current mbuf.

         */
        if ((off == 0 || offp) && len <= n->m_len - off)
                goto ok;
         */
        if ((off == 0 || offp) && len <= n->m_len - off)
                goto ok;


@@ -248,12 +267,12 @@ m_pulldown(struct mbuf *m, int off, int len, int *offp)
 #endif
 
        /*
 #endif
 
        /*

-        * when len < n->m_len - off and off != 0, it is a special case.
+        * when len <= n->m_len - off and off != 0, it is a special case.

         * len bytes from <n, off> sits in single mbuf, but the caller does
         * not like the starting position (off).
         * chop the current mbuf into two pieces, set off to 0.
         */
         * len bytes from <n, off> sits in single mbuf, but the caller does
         * not like the starting position (off).
         * chop the current mbuf into two pieces, set off to 0.
         */

-       if (len < n->m_len - off) {
+       if (len <= n->m_len - off) {

                o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
                if (o == NULL) {
                        m_freem(m);
                o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
                if (o == NULL) {
                        m_freem(m);


@@ -271,6 +290,8 @@ m_pulldown(struct mbuf *m, int off, int len, int *offp)
         * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
         * and construct contiguous mbuf with m_len == len.
         * note that hlen + tlen == len, and tlen > 0.
         * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
         * and construct contiguous mbuf with m_len == len.
         * note that hlen + tlen == len, and tlen > 0.

+        *
+        * Read these variables as head length and tail length

         */
        hlen = n->m_len - off;
        tlen = len - hlen;
         */
        hlen = n->m_len - off;
        tlen = len - hlen;


@@ -294,13 +315,19 @@ m_pulldown(struct mbuf *m, int off, int len, int *offp)
        if ((n->m_flags & M_EXT) == 0)
                sharedcluster = 0;
        else {
        if ((n->m_flags & M_EXT) == 0)
                sharedcluster = 0;
        else {

-               if (n->m_ext.ext_free)
+               if (m_get_ext_free(n) != NULL)

                        sharedcluster = 1;
                else if (m_mclhasreference(n))
                        sharedcluster = 1;
                else
                        sharedcluster = 0;
        }
                        sharedcluster = 1;
                else if (m_mclhasreference(n))
                        sharedcluster = 1;
                else
                        sharedcluster = 0;
        }

+
+       /*
+        * If we have enough space left in current mbuf to accomodate
+        * tail length, copy tail length worth of data starting with next mbuf
+        * and adjust the length of next one accordingly.
+        */

        if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
         && !sharedcluster) {
                m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
        if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
         && !sharedcluster) {
                m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);


@@ -308,8 +335,15 @@ m_pulldown(struct mbuf *m, int off, int len, int *offp)
                m_adj(n->m_next, tlen);
                goto ok;
        }
                m_adj(n->m_next, tlen);
                goto ok;
        }

-       if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
-        && !sharedcluster) {
+
+       /*
+        * If have enough leading space in next mbuf to accomodate head length
+        * of current mbuf, and total resulting length of next mbuf is greater
+        * than or equal to requested len bytes, then just copy hlen from
+        * current to the next one and adjust sizes accordingly.
+        */
+       if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen &&
+           (n->m_next->m_len + hlen) >= len && !sharedcluster) {

                n->m_next->m_data -= hlen;
                n->m_next->m_len += hlen;
                bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
                n->m_next->m_data -= hlen;
                n->m_next->m_len += hlen;
                bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);


@@ -664,9 +698,8 @@ m_tag_init(struct mbuf *m, int all)
         * (e.g. m_dup_pkthdr), don't zero them out.
         */
        if (all) {
         * (e.g. m_dup_pkthdr), don't zero them out.
         */
        if (all) {

-               bzero(m_pftag(m), sizeof (struct pf_mtag));
-               bzero(&m->m_pkthdr.proto_mtag, sizeof (m->m_pkthdr.proto_mtag));
-               bzero(&m->m_pkthdr.necp_mtag, sizeof (m->m_pkthdr.necp_mtag));
+               bzero(&m->m_pkthdr.builtin_mtag._net_mtag,
+                   sizeof (m->m_pkthdr.builtin_mtag._net_mtag));

        }
 }
 
        }
 }
 


@@ -825,27 +858,75 @@ m_service_class_from_val(u_int32_t v)
 }
 
 uint16_t
 }
 
 uint16_t

-m_adj_sum16(struct mbuf *m, uint32_t start, uint32_t ulpoff, uint32_t sum)
+m_adj_sum16(struct mbuf *m, uint32_t start, uint32_t dataoff,
+    uint32_t datalen, uint32_t sum)

 {
 {

-       int len = (ulpoff - start);
+       uint32_t total_sub = 0;                 /* total to subtract */
+       uint32_t mlen = m_pktlen(m);            /* frame length */
+       uint32_t bytes = (dataoff + datalen);   /* bytes covered by sum */
+       int len;
+
+       ASSERT(bytes <= mlen);

 
 

+       /*
+        * Take care of excluding (len > 0) or including (len < 0)
+        * extraneous octets at the beginning of the packet, taking
+        * into account the start offset.
+        */
+       len = (dataoff - start);
+       if (len > 0)
+               total_sub = m_sum16(m, start, len);
+       else if (len < 0)
+               sum += m_sum16(m, dataoff, -len);
+
+       /*
+        * Take care of excluding any postpended extraneous octets.
+        */
+       len = (mlen - bytes);

        if (len > 0) {
        if (len > 0) {

-               uint32_t adj = m_sum16(m, start, len);
-               if (adj >= sum)
-                       sum = ~(adj - sum) & 0xffff;
+               struct mbuf *m0 = m;
+               uint32_t extra = m_sum16(m, bytes, len);
+               uint32_t off = bytes, off0 = off;
+
+               while (off > 0) {
+                       if (__improbable(m == NULL)) {
+                               panic("%s: invalid mbuf chain %p [off %u, "
+                                   "len %u]", __func__, m0, off0, len);
+                               /* NOTREACHED */
+                       }
+                       if (off < m->m_len)
+                               break;
+                       off -= m->m_len;
+                       m = m->m_next;
+               }
+
+               /* if we started on odd-alignment, swap the value */
+               if ((uintptr_t)(mtod(m, uint8_t *) + off) & 1)
+                       total_sub += ((extra << 8) & 0xffff) | (extra >> 8);
+               else
+                       total_sub += extra;
+
+               total_sub = (total_sub >> 16) + (total_sub & 0xffff);
+       }
+
+       /*
+        * 1's complement subtract any extraneous octets.
+        */
+       if (total_sub != 0) {
+               if (total_sub >= sum)
+                       sum = ~(total_sub - sum) & 0xffff;

                else
                else

-                       sum -= adj;
-       } else if (len < 0) {
-               sum += m_sum16(m, ulpoff, -len);
+                       sum -= total_sub;

        }
 
        }
 

-       ADDCARRY(sum);
+       /* fold 32-bit to 16-bit */
+       sum = (sum >> 16) + (sum & 0xffff);     /* 17-bit */
+       sum = (sum >> 16) + (sum & 0xffff);     /* 16-bit + carry */
+       sum = (sum >> 16) + (sum & 0xffff);     /* final carry */

 
 

-       return (sum);
+       return (sum & 0xffff);

 }
 
 }
 

-extern int cpu_in_cksum(struct mbuf *m, int len, int off, uint32_t initial_sum);
-

 uint16_t
 m_sum16(struct mbuf *m, uint32_t off, uint32_t len)
 {
 uint16_t
 m_sum16(struct mbuf *m, uint32_t off, uint32_t len)
 {


@@ -859,9 +940,10 @@ m_sum16(struct mbuf *m, uint32_t off, uint32_t len)
         * a M_PKTHDR one.
         */
        if ((mlen = m_length2(m, NULL)) < (off + len)) {
         * a M_PKTHDR one.
         */
        if ((mlen = m_length2(m, NULL)) < (off + len)) {

-               panic("%s: mbuf len (%d) < off+len (%d+%d)\n", __func__,
-                   mlen, off, len);
+               panic("%s: mbuf %p len (%d) < off+len (%d+%d)\n", __func__,
+                   m, mlen, off, len);
+               /* NOTREACHED */

        }
 
        }
 

-       return (~cpu_in_cksum(m, len, off, 0) & 0xffff);
+       return (os_cpu_in_cksum_mbuf(m, len, off, 0));

 }
 }