Check in hooks to fix checksum offload on bge devices. Empirical
observation is that some 570x devices can get themselves into a state where they miscompute off-loaded TCP or UDP checksums on packets so small that Ethernet padding is required. Further obsevation suggests that the bge checksum-offload hardware is adding those padding bytes into its TCP checksum computation. (Once a 5700 gets in this state, even a warm boot won't fix it: it needs a hard powerdown.) Work around the problem by padding such runts with zeros: even if the checksum-offload adds in extra zeros, the resulting sum will be correct. Also, dont trust the checksum-offload on received packets smaller than the minimum ethernet frame, in case the Rx-side has a similar bug. Finally, on packets where we do trust the outboard Rx-side TCP or UDP checksum, the bge did not include the pseudo-header. Set the M_CSUM_NO_PSEUDOHDR bit as well as M_CSUM_DATA, and rely on udp_input() or tcp_input() adding in the sum via in_cksum_phdr().
This commit is contained in:
jonathan
parent
96538bcf9e
commit
215937cb45
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@ -1,4 +1,4 @@
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/* $NetBSD: if_bge.c,v 1.45 2003/08/22 03:03:20 jonathan Exp $ */
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/* $NetBSD: if_bge.c,v 1.46 2003/08/22 03:32:35 jonathan Exp $ */
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/*
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* Copyright (c) 2001 Wind River Systems
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@ -79,7 +79,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: if_bge.c,v 1.45 2003/08/22 03:03:20 jonathan Exp $");
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__KERNEL_RCSID(0, "$NetBSD: if_bge.c,v 1.46 2003/08/22 03:32:35 jonathan Exp $");
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#include "bpfilter.h"
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#include "vlan.h"
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@ -123,6 +123,8 @@ __KERNEL_RCSID(0, "$NetBSD: if_bge.c,v 1.45 2003/08/22 03:03:20 jonathan Exp $")
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#include <uvm/uvm_extern.h>
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#define ETHER_MIN_NOPAD (ETHER_MIN_LEN - ETHER_CRC_LEN) /* i.e., 60 */
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int bge_probe(struct device *, struct cfdata *, void *);
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void bge_attach(struct device *, struct device *, void *);
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void bge_release_resources(struct bge_softc *);
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@ -132,6 +134,7 @@ void bge_rxeof(struct bge_softc *);
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void bge_tick(void *);
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void bge_stats_update(struct bge_softc *);
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int bge_encap(struct bge_softc *, struct mbuf *, u_int32_t *);
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static __inline int bge_cksum_pad(struct mbuf *pkt);
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static __inline int bge_compact_dma_runt(struct mbuf *pkt);
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int bge_intr(void *);
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@ -2472,18 +2475,23 @@ bge_rxeof(sc)
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bpf_mtap(ifp->if_bpf, m);
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#endif
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if ((sc->bge_quirks & BGE_QUIRK_CSUM_BROKEN) == 0) {
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m->m_pkthdr.csum_flags |= M_CSUM_IPv4;
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if ((cur_rx->bge_ip_csum ^ 0xffff) != 0)
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m->m_pkthdr.csum_flags |= M_CSUM_IPv4_BAD;
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#if 0 /* XXX appears to be broken */
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if (cur_rx->bge_flags & BGE_RXBDFLAG_TCP_UDP_CSUM) {
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m->m_pkthdr.csum_data =
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cur_rx->bge_tcp_udp_csum;
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m->m_pkthdr.csum_flags |=
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(M_CSUM_TCPv4|M_CSUM_UDPv4|M_CSUM_DATA);
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}
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#endif
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m->m_pkthdr.csum_flags |= M_CSUM_IPv4;
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if ((cur_rx->bge_ip_csum ^ 0xffff) != 0)
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m->m_pkthdr.csum_flags |= M_CSUM_IPv4_BAD;
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/*
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* Rx transport checksum-offload may also
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* have bugs with packets which, when transmitted,
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* were `runts' requiring padding.
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*/
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if (cur_rx->bge_flags & BGE_RXBDFLAG_TCP_UDP_CSUM &&
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(/* (sc->_bge_quirks & BGE_QUIRK_SHORT_CKSUM_BUG) == 0 ||*/
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m->m_pkthdr.len >= ETHER_MIN_NOPAD)) {
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m->m_pkthdr.csum_data =
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cur_rx->bge_tcp_udp_csum;
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m->m_pkthdr.csum_flags |=
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(M_CSUM_TCPv4|M_CSUM_UDPv4|
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M_CSUM_DATA|M_CSUM_NO_PSEUDOHDR);
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}
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/*
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@ -2751,6 +2759,59 @@ bge_stats_update(sc)
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#endif
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}
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/*
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* Pad outbound frame to ETHER_MIN_NOPAD for an unusual reason.
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* The bge hardware will pad out Tx runts to ETHER_MIN_NOPAD,
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* but when such padded frames employ the bge IP/TCP checksum offload,
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* the hardware checksum assist gives incorrect results (possibly
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* from incorporating its own padding into the UDP/TCP checksum; who knows).
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* If we pad such runts with zeros, the onboard checksum comes out correct.
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*/
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static __inline int
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bge_cksum_pad(struct mbuf *pkt)
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{
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struct mbuf *last = NULL;
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int padlen;
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padlen = ETHER_MIN_NOPAD - pkt->m_pkthdr.len;
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/* if there's only the packet-header and we can pad there, use it. */
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if (pkt->m_pkthdr.len == pkt->m_len &&
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!M_READONLY(pkt) && M_TRAILINGSPACE(pkt) >= padlen) {
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last = pkt;
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} else {
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/*
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* Walk packet chain to find last mbuf. We will either
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* pad there, or append a new mbuf and pad it
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* (thus perhaps avoiding the bcm5700 dma-min bug).
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*/
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for (last = pkt; last->m_next != NULL; last = last->m_next) {
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(void) 0; /* do nothing*/
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}
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/* `last' now points to last in chain. */
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if (!M_READONLY(last) && M_TRAILINGSPACE(last) >= padlen) {
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(void) 0; /* we can pad here, in-place. */
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} else {
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/* Allocate new empty mbuf, pad it. Compact later. */
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struct mbuf *n;
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MGET(n, M_DONTWAIT, MT_DATA);
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n->m_len = 0;
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last->m_next = n;
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last = n;
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}
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}
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#ifdef DEBUG
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KASSERT(M_WRITABLE(last), ("to-pad mbuf not writeable\n"));
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KASSERT(M_TRAILINGSPACE(last) >= padlen, ("insufficient space to pad\n"));
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#endif
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/* Now zero the pad area, to avoid the bge cksum-assist bug */
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memset(mtod(last, caddr_t) + last->m_len, 0, padlen);
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last->m_len += padlen;
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pkt->m_pkthdr.len += padlen;
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return 0;
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}
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/*
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* Compact outbound packets to avoid bug with DMA segments less than 8 bytes.
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@ -2896,6 +2957,24 @@ bge_encap(sc, m_head, txidx)
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csum_flags |= BGE_TXBDFLAG_TCP_UDP_CSUM;
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}
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/*
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* If we were asked to do an outboard checksum, and the NIC
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* has the bug where it sometimes adds in the Ethernet padding,
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* explicitly pad with zeros so the cksum will be correct either way.
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* (For now, do this for all chip versions, until newer
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* are confirmed to not require the workaround.)
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*/
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if ((csum_flags & BGE_TXBDFLAG_TCP_UDP_CSUM) == 0 ||
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#ifdef notyet
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(sc->bge_quirks & BGE_QUIRK_SHORT_CKSUM_BUG) == 0 ||
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#endif
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m_head->m_pkthdr.len >= ETHER_MIN_NOPAD)
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goto check_dma_bug;
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if (bge_cksum_pad(m_head) != 0)
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return ENOBUFS;
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check_dma_bug:
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if (!(sc->bge_quirks & BGE_QUIRK_5700_SMALLDMA))
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goto doit;
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/*
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