From 792f1d639443c3895df82306e13bb144627ad6bc Mon Sep 17 00:00:00 2001 From: Stefan Weil Date: Sat, 30 Apr 2011 22:40:07 +0200 Subject: [PATCH] eepro100: Pad received short frames QEMU sends frames smaller than 60 bytes to ethernet nics. Such frames are rejected by real NICs and their emulations. To avoid this behaviour, other NIC emulations pad received frames. This patch enables this workaround for eepro100, too. All related code is marked with CONFIG_PAD_RECEIVED_FRAMES, so we can drop this in case QEMU's networking code is ever changed. Signed-off-by: Stefan Weil Signed-off-by: Michael S. Tsirkin --- hw/eepro100.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/hw/eepro100.c b/hw/eepro100.c index 848bf79461..ab5c699c9d 100644 --- a/hw/eepro100.c +++ b/hw/eepro100.c @@ -48,6 +48,15 @@ #include "eeprom93xx.h" #include "sysemu.h" +/* QEMU sends frames smaller than 60 bytes to ethernet nics. + * Such frames are rejected by real nics and their emulations. + * To avoid this behaviour, other nic emulations pad received + * frames. The following definition enables this padding for + * eepro100, too. We keep the define around in case it might + * become useful the future if the core networking is ever + * changed to pad short packets itself. */ +#define CONFIG_PAD_RECEIVED_FRAMES + #define KiB 1024 /* Debug EEPRO100 card. */ @@ -1640,19 +1649,32 @@ static ssize_t nic_receive(VLANClientState *nc, const uint8_t * buf, size_t size */ EEPRO100State *s = DO_UPCAST(NICState, nc, nc)->opaque; uint16_t rfd_status = 0xa000; +#if defined(CONFIG_PAD_RECEIVED_FRAMES) + uint8_t min_buf[60]; +#endif static const uint8_t broadcast_macaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; +#if defined(CONFIG_PAD_RECEIVED_FRAMES) + /* Pad to minimum Ethernet frame length */ + if (size < sizeof(min_buf)) { + memcpy(min_buf, buf, size); + memset(&min_buf[size], 0, sizeof(min_buf) - size); + buf = min_buf; + size = sizeof(min_buf); + } +#endif + if (s->configuration[8] & 0x80) { /* CSMA is disabled. */ logout("%p received while CSMA is disabled\n", s); return -1; +#if !defined(CONFIG_PAD_RECEIVED_FRAMES) } else if (size < 64 && (s->configuration[7] & BIT(0))) { /* Short frame and configuration byte 7/0 (discard short receive) set: * Short frame is discarded */ logout("%p received short frame (%zu byte)\n", s, size); s->statistics.rx_short_frame_errors++; -#if 0 return -1; #endif } else if ((size > MAX_ETH_FRAME_SIZE + 4) && !(s->configuration[18] & BIT(3))) { @@ -1731,9 +1753,11 @@ static ssize_t nic_receive(VLANClientState *nc, const uint8_t * buf, size_t size "(%zu bytes); data truncated\n", rfd_size, size); size = rfd_size; } +#if !defined(CONFIG_PAD_RECEIVED_FRAMES) if (size < 64) { rfd_status |= 0x0080; } +#endif TRACE(OTHER, logout("command 0x%04x, link 0x%08x, addr 0x%08x, size %u\n", rfd_command, rx.link, rx.rx_buf_addr, rfd_size)); stw_phys(s->ru_base + s->ru_offset + offsetof(eepro100_rx_t, status),