[PATCH net] net: ftmac100: do not reject packets bigger than 1514
From: Sergei Antonov <hidden>
Date: 2022-10-12 13:46:07
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Dispite datasheet [1] saying the controller should allow incoming packets of length >=1518, it only allows packets of length <=1514. Since 1518 is a standard Ethernet maximum frame size, and it can easily be encountered (in SSH for example), fix this behaviour: * Set FTMAC100_MACCR_RX_FTL in the MAC Control Register. * Check for packet size > 1518 in ftmac100_rx_packet_error(). [1] https://bitbucket.org/Kasreyn/mkrom-uc7112lx/src/master/documents/FIC8120_DS_v1.2.pdf Fixes: 8d77c036b57c ("net: add Faraday FTMAC100 10/100 Ethernet driver") Signed-off-by: Sergei Antonov <redacted> --- drivers/net/ethernet/faraday/ftmac100.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/faraday/ftmac100.c b/drivers/net/ethernet/faraday/ftmac100.c
index d95d78230828..34d0284079ff 100644
--- a/drivers/net/ethernet/faraday/ftmac100.c
+++ b/drivers/net/ethernet/faraday/ftmac100.c@@ -154,6 +154,7 @@ static void ftmac100_set_mac(struct ftmac100 *priv, const unsigned char *mac) FTMAC100_MACCR_CRC_APD | \ FTMAC100_MACCR_FULLDUP | \ FTMAC100_MACCR_RX_RUNT | \ + FTMAC100_MACCR_RX_FTL | \ FTMAC100_MACCR_RX_BROADPKT) static int ftmac100_start_hw(struct ftmac100 *priv)
@@ -320,6 +321,7 @@ static bool ftmac100_rx_packet_error(struct ftmac100 *priv, { struct net_device *netdev = priv->netdev; bool error = false; + const unsigned int length = ftmac100_rxdes_frame_length(rxdes); if (unlikely(ftmac100_rxdes_rx_error(rxdes))) { if (net_ratelimit())
@@ -337,9 +339,16 @@ static bool ftmac100_rx_packet_error(struct ftmac100 *priv, error = true; } - if (unlikely(ftmac100_rxdes_frame_too_long(rxdes))) { + /* The frame-too-long flag 'FTMAC100_RXDES0_FTL' is described in the + * datasheet as: "When set, it indicates that the received packet + * length exceeds 1518 bytes." But testing shows that it is also set + * when packet length is equal to 1518. + * Since 1518 is a standard Ethernet maximum frame size, let it pass + * and only trigger an error when packet length really exceeds it. + */ + if (unlikely(ftmac100_rxdes_frame_too_long(rxdes) && length > 1518)) { if (net_ratelimit()) - netdev_info(netdev, "rx frame too long\n"); + netdev_info(netdev, "rx frame too long (%u)\n", length); netdev->stats.rx_length_errors++; error = true;
--
2.34.1