From 8a2a20e71e2909f84dab47e51dfda9e292a6c1ae Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Fri, 7 Oct 2016 15:02:13 +0100 Subject: [PATCH] ltq-ptm: Support 1508-byte MTU for RFC4638 Tested with VDSL on TP-Link WD8970, I see full 1500-byte PPP data frames, which end up being 1526 byte Ethernet frames (including Ethernet+VLAN headers) on the wire. Fixes: FS#210 Signed-off-by: David Woodhouse --- package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_adsl.c | 12 +++++++++++- package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_vdsl.c | 12 +++++++++++- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_adsl.c b/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_adsl.c index dc75b12cca..b096b0a702 100644 --- a/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_adsl.c +++ b/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_adsl.c @@ -128,6 +128,7 @@ static int ptm_stop(struct net_device *); static unsigned int ptm_poll(int, unsigned int); static int ptm_napi_poll(struct napi_struct *, int); static int ptm_hard_start_xmit(struct sk_buff *, struct net_device *); +static int ptm_change_mtu(struct net_device *, int); static int ptm_ioctl(struct net_device *, struct ifreq *, int); static void ptm_tx_timeout(struct net_device *); @@ -246,7 +247,7 @@ static struct net_device_ops g_ptm_netdev_ops = { .ndo_start_xmit = ptm_hard_start_xmit, .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = eth_mac_addr, - .ndo_change_mtu = eth_change_mtu, + .ndo_change_mtu = ptm_change_mtu, .ndo_do_ioctl = ptm_ioctl, .ndo_tx_timeout = ptm_tx_timeout, }; @@ -451,6 +452,15 @@ PTM_HARD_START_XMIT_FAIL: return NETDEV_TX_OK; } +static int ptm_change_mtu(struct net_device *dev, int mtu) +{ + /* Allow up to 1508 bytes, for RFC4638 */ + if (mtu < 68 || mtu > ETH_DATA_LEN + 8) + return -EINVAL; + dev->mtu = mtu; + return 0; +} + static int ptm_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) { int ndev; diff --git a/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_vdsl.c b/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_vdsl.c index 41464e6c27..bc27c270d8 100644 --- a/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_vdsl.c +++ b/package/kernel/lantiq/ltq-ptm/src/ifxmips_ptm_vdsl.c @@ -74,6 +74,7 @@ static int ptm_stop(struct net_device *); static unsigned int ptm_poll(int, unsigned int); static int ptm_napi_poll(struct napi_struct *, int); static int ptm_hard_start_xmit(struct sk_buff *, struct net_device *); +static int ptm_change_mtu(struct net_device *, int); static int ptm_ioctl(struct net_device *, struct ifreq *, int); static void ptm_tx_timeout(struct net_device *); @@ -114,7 +115,7 @@ static struct net_device_ops g_ptm_netdev_ops = { .ndo_start_xmit = ptm_hard_start_xmit, .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = eth_mac_addr, - .ndo_change_mtu = eth_change_mtu, + .ndo_change_mtu = ptm_change_mtu, .ndo_do_ioctl = ptm_ioctl, .ndo_tx_timeout = ptm_tx_timeout, }; @@ -358,6 +359,15 @@ PTM_HARD_START_XMIT_FAIL: return 0; } +static int ptm_change_mtu(struct net_device *dev, int mtu) +{ + /* Allow up to 1508 bytes, for RFC4638 */ + if (mtu < 68 || mtu > ETH_DATA_LEN + 8) + return -EINVAL; + dev->mtu = mtu; + return 0; +} + static int ptm_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) { ASSERT(dev == g_net_dev[0], "incorrect device"); -- 2.30.2