Simplify logic for LRO packet tracking in ix(4). Protect against

integer overflow although it should not happen.

test and OK jan@

diff --git a/sys/dev/pci/if_ix.c b/sys/dev/pci/if_ix.c
index 80df360..e2a5edc 100644 (file)
--- a/sys/dev/pci/if_ix.c
+++ b/sys/dev/pci/if_ix.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_ix.c,v 1.201 2023/07/27 20:21:25 jan Exp $ */
+/*     $OpenBSD: if_ix.c,v 1.202 2023/07/28 20:25:08 bluhm Exp $       */
 
 /******************************************************************************
 
@@ -3225,30 +3225,27 @@ ixgbe_rxeof(struct rx_ring *rxr)
                sendmp = rxbuf->fmp;
                rxbuf->buf = rxbuf->fmp = NULL;
 
-               if (sendmp != NULL) { /* secondary frag */
-                       sendmp->m_pkthdr.len += mp->m_len;
-
-                       /*
-                        * This function iterates over interleaved descriptors.
-                        * Thus, we reuse ph_mss as global segment counter per
-                        * TCP connection, instead of introducing a new variable
-                        * in m_pkthdr.
-                        */
-                       if (rsccnt)
-                               sendmp->m_pkthdr.ph_mss += rsccnt - 1;
-               } else {
+               if (sendmp == NULL) {
                        /* first desc of a non-ps chain */
                        sendmp = mp;
-                       sendmp->m_pkthdr.len = mp->m_len;
-                       if (rsccnt)
-                               sendmp->m_pkthdr.ph_mss = rsccnt - 1;
+                       sendmp->m_pkthdr.len = 0;
+                       sendmp->m_pkthdr.ph_mss = 0;
 #if NVLAN > 0
                        if (sc->vlan_stripping && staterr & IXGBE_RXD_STAT_VP) {
                                sendmp->m_pkthdr.ether_vtag = vtag;
-                               sendmp->m_flags |= M_VLANTAG;
+                               SET(sendmp->m_flags, M_VLANTAG);
                        }
 #endif
                }
+               sendmp->m_pkthdr.len += mp->m_len;
+               /*
+                * This function iterates over interleaved descriptors.
+                * Thus, we reuse ph_mss as global segment counter per
+                * TCP connection, instead of introducing a new variable
+                * in m_pkthdr.
+                */
+               if (rsccnt)
+                       sendmp->m_pkthdr.ph_mss += rsccnt - 1;
 
                /* Pass the head pointer on */
                if (eop == 0) {
@@ -3296,7 +3293,8 @@ ixgbe_rxeof(struct rx_ring *rxr)
                                 * mark it as TSO, set a correct mss,
                                 * and recalculate the TCP checksum.
                                 */
-                               paylen = sendmp->m_pkthdr.len - hdrlen;
+                               paylen = sendmp->m_pkthdr.len > hdrlen ?
+                                   sendmp->m_pkthdr.len - hdrlen : 0;
                                if (ext.tcp && paylen >= pkts) {
                                        SET(sendmp->m_pkthdr.csum_flags,
                                            M_TCP_TSO);