xnu-201.19.tar.gz

[apple/xnu.git] / bsd / netinet / tcp_output.c

diff --git a/bsd/netinet/tcp_output.c b/bsd/netinet/tcp_output.c
index c648029c645b6c1f936d7070faabb8a69f114ec3..56043b0597ff688a4cd57d48dfdd3fc2d098e54e 100644 (file)
--- a/bsd/netinet/tcp_output.c
+++ b/bsd/netinet/tcp_output.c
@@ -93,6 +93,7 @@
 #endif
 #include <sys/kdebug.h>
 
+
 #define DBG_LAYER_BEG          NETDBG_CODE(DBG_NETTCP, 1)
 #define DBG_LAYER_END          NETDBG_CODE(DBG_NETTCP, 3)
 #define DBG_FNC_TCP_OUTPUT     NETDBG_CODE(DBG_NETTCP, (4 << 8) | 1)
@@ -128,14 +129,19 @@ tcp_output(tp)
 #if INET6
        int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV4) == 0;
 #endif
+       int    last_off;
+       int    m_off;
+       struct mbuf *m_last = 0;
+       struct mbuf *m_head = 0;
+
 
        KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
+
        KERNEL_DEBUG(DBG_LAYER_BEG,
                     ((tp->t_template->tt_dport << 16) | tp->t_template->tt_sport),
                     (((tp->t_template->tt_src.s_addr & 0xffff) << 16) |
                      (tp->t_template->tt_dst.s_addr & 0xffff)),
                     0,0,0);
-
        /*
         * Determine length of data that should be transmitted,
         * and flags that will be used.
@@ -563,33 +569,57 @@ send:
                m->m_len += hdrlen;
                m->m_data -= hdrlen;
 #else
-               MGETHDR(m, M_DONTWAIT, MT_HEADER);
-               if (m == NULL) {
-                       error = ENOBUFS;
-                       goto out;
-               }
+               m = NULL;
 #if INET6
                if (MHLEN < hdrlen + max_linkhdr) {
+                       MGETHDR(m, M_DONTWAIT, MT_HEADER);
+                       if (m == NULL) {
+                               error = ENOBUFS;
+                               goto out;
+                       }
                        MCLGET(m, M_DONTWAIT);
                        if ((m->m_flags & M_EXT) == 0) {
                                m_freem(m);
                                error = ENOBUFS;
                                goto out;
                        }
+                       m->m_data += max_linkhdr;
+                       m->m_len = hdrlen;
                }
 #endif
-               m->m_data += max_linkhdr;
-               m->m_len = hdrlen;
                if (len <= MHLEN - hdrlen - max_linkhdr) {
+                       if (m == NULL) {
+                               MGETHDR(m, M_DONTWAIT, MT_HEADER);
+                               if (m == NULL) {
+                                       error = ENOBUFS;
+                                       goto out;
+                               }
+                               m->m_data += max_linkhdr;
+                               m->m_len = hdrlen;
+                       }
                        m_copydata(so->so_snd.sb_mb, off, (int) len,
                            mtod(m, caddr_t) + hdrlen);
                        m->m_len += len;
                } else {
-                       m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len);
-                       if (m->m_next == 0) {
-                               (void) m_free(m);
-                               error = ENOBUFS;
-                               goto out;
+                       if (m != NULL) {
+                               m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len);
+                               if (m->m_next == 0) {
+                                       (void) m_free(m);
+                                       error = ENOBUFS;
+                                       goto out;
+                               }
+                       } else {
+                               if (m_head != so->so_snd.sb_mb || last_off != off)
+                                       m_last = NULL;
+                               last_off = off + len;
+                               m_head = so->so_snd.sb_mb;
+
+                               if ((m = m_copym_with_hdrs(so->so_snd.sb_mb, off, (int) len, M_DONTWAIT, &m_last, &m_off)) == NULL) {
+                                       error = ENOBUFS;
+                                       goto out;
+                               }
+                               m->m_data += max_linkhdr;
+                               m->m_len = hdrlen;
                        }
                }
 #endif
@@ -701,6 +731,7 @@ send:
                 */
                tp->snd_up = tp->snd_una;               /* drag it along */
 
+
        /*
         * Put TCP length in extended header, and then
         * checksum extended header and data.
@@ -857,8 +888,6 @@ send:
        KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
                   (((thtoti(th)->ti_src.s_addr & 0xffff) << 16) | (thtoti(th)->ti_dst.s_addr & 0xffff)),
                    th->th_seq, th->th_ack, th->th_win);
-
-
 #if 1
        /*
         * See if we should do MTU discovery.  We do it only if the following