From a35e7eaa1abf78124ce7adefbd1baaa6e6096ec6 Mon Sep 17 00:00:00 2001 From: Don Lewis Date: Sun, 25 May 2003 05:04:26 +0000 Subject: [PATCH] Always set the hardware parse bit in the IPCB structure when this structure, which is new to the 82550 and 82551, is used to transmit a packet. This appears to fix the packet truncation problem that was observed when using 82550-based fxp cards to transmit ICMP or fragmented UDP packets of certain lengths which only had one to three bytes in the second and final mbuf of the packet. This matches a note in the "Intel 8255x 10/100 Mbps Ethernet Controller Family Open Source Software Developer Manual", which says that the hardware parse bit should be set when sending these types of packets. There have also been unconfirmed reports of similar problems when transmitting TCP packets, which should not be affected by the above mentioned change because the hardware parse bit was already being set if the stack requested hardware checksumming of the packet. If the problem remains, the use of the IPCB structure can be disabled to cause the driver to fall back to using the older 82559 interface with 82550-based cards by setting hint.fxp.UNIT_NUMBER.ipcbxmit_disable to a non-zero value at boot time, or using kenv to set this variable before using kldload to load the fxp driver. Approved by: re (jhb) --- sys/dev/fxp/if_fxp.c | 45 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 41 insertions(+), 4 deletions(-) diff --git a/sys/dev/fxp/if_fxp.c b/sys/dev/fxp/if_fxp.c index 1124ede8e1c0..881101defe84 100644 --- a/sys/dev/fxp/if_fxp.c +++ b/sys/dev/fxp/if_fxp.c @@ -383,7 +383,7 @@ fxp_attach(device_t dev) u_int32_t val; u_int16_t data, myea[ETHER_ADDR_LEN / 2]; int i, rid, m1, m2, prefer_iomap, maxtxseg; - int s; + int s, ipcbxmit_disable; sc->dev = dev; callout_handle_init(&sc->stat_ch); @@ -582,9 +582,31 @@ fxp_attach(device_t dev) * and later chips. Note: we need extended TXCB support * too, but that's already enabled by the code above. * Be careful to do this only on the right devices. + * + * At least some 82550 cards probed as "chip=0x12298086 rev=0x0d" + * truncate packets that end with an mbuf containing 1 to 3 bytes + * when used with this feature enabled in the previous version of the + * driver. This problem appears to be fixed now that the driver + * always sets the hardware parse bit in the IPCB structure, which + * the "Intel 8255x 10/100 Mbps Ethernet Controller Family Open + * Source Software Developer Manual" says is necessary in the + * cases where packet truncation was observed. + * + * The device hint "hint.fxp.UNIT_NUMBER.ipcbxmit_disable" + * allows this feature to be disabled at boot time. + * + * If fxp is not compiled into the kernel, this feature may also + * be disabled at run time: + * # kldunload fxp + * # kenv hint.fxp.0.ipcbxmit_disable=1 + * # kldload fxp */ - if (sc->revision == FXP_REV_82550 || sc->revision == FXP_REV_82550_C) { + if (resource_int_value("fxp", device_get_unit(dev), "ipcbxmit_disable", + &ipcbxmit_disable) != 0) + ipcbxmit_disable = 0; + if (ipcbxmit_disable == 0 && (sc->revision == FXP_REV_82550 || + sc->revision == FXP_REV_82550_C)) { sc->rfa_size = sizeof (struct fxp_rfa); sc->tx_cmd = FXP_CB_COMMAND_IPCBXMIT; sc->flags |= FXP_FLAG_EXT_RFA; @@ -1276,6 +1298,23 @@ fxp_start_body(struct ifnet *ifp) */ txp = sc->fxp_desc.tx_last->tx_next; + /* + * A note in Appendix B of the Intel 8255x 10/100 Mbps + * Ethernet Controller Family Open Source Software + * Developer Manual says: + * Using software parsing is only allowed with legal + * TCP/IP or UDP/IP packets. + * ... + * For all other datagrams, hardware parsing must + * be used. + * Software parsing appears to truncate ICMP and + * fragmented UDP packets that contain one to three + * bytes in the second (and final) mbuf of the packet. + */ + if (sc->flags & FXP_FLAG_EXT_RFA) + txp->tx_cb->ipcb_ip_activation_high = + FXP_IPCB_HARDWAREPARSING_ENABLE; + /* * Deal with TCP/IP checksum offload. Note that * in order for TCP checksum offload to work, @@ -1287,8 +1326,6 @@ fxp_start_body(struct ifnet *ifp) if (mb_head->m_pkthdr.csum_flags) { if (mb_head->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { - txp->tx_cb->ipcb_ip_activation_high = - FXP_IPCB_HARDWAREPARSING_ENABLE; txp->tx_cb->ipcb_ip_schedule = FXP_IPCB_TCPUDP_CHECKSUM_ENABLE; if (mb_head->m_pkthdr.csum_flags & CSUM_TCP)