| Message ID | CANn89iKStHAwVZtpgQMzEpByGYG2FKpjSQsJFT-9qQmjw+KJ8g@mail.gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
Or its the lines with CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS ? What arch is it ? On Thu, Sep 20, 2012 at 2:45 PM, Eric Dumazet <edumazet@google.com> wrote: > I guess you only need to make sure 14 bytes of ethernet header are > available before eth_type_trans(skb, dev); > > diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c > index 61c621e..ffe5f84 100644 > --- a/net/mac80211/rx.c > +++ b/net/mac80211/rx.c > @@ -1795,9 +1795,13 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx) > > if (skb) { > /* deliver to local stack */ > - skb->protocol = eth_type_trans(skb, dev); > - memset(skb->cb, 0, sizeof(skb->cb)); > - netif_receive_skb(skb); > + if (pskb_may_pull(skb, sizeof(struct ethhdr))) { > + skb->protocol = eth_type_trans(skb, dev); > + memset(skb->cb, 0, sizeof(skb->cb)); > + netif_receive_skb(skb); > + } else { > + kfree_skb(skb); > + } > } > } > > > On Thu, Sep 20, 2012 at 2:40 PM, Eric Dumazet <edumazet@google.com> wrote: >> OK, but which netif_receive_skb(), as I count 5 occurrences in >> net/mac80211/rx.c ? >> >> Instead of skb_linearize() calls >> >> you could try several values of XXX in >> >> pskb_may_pull(skb, XXX) >> >> So that you make sure XXX bytes are available in skb->head, and not >> the whole frame. >> >> One you know the limit for XXX, it might give a clue where a >> pskb_may_pull(skb, XXX) is missing. >> >> On Thu, Sep 20, 2012 at 2:35 PM, Johannes Berg >> <johannes@sipsolutions.net> wrote: >>> Hi, >>> >>>> > 56138f5 iwlwifi: dont pull too much payload in skb head >>>> > 3edaf3e mac80211: manage AP netdev carrier state >>>> >>>> The second patch (AP carrier state) actually exposed a connman issue >>>> which I fixed and submitted a connman patch: >>>> http://lists.connman.net/pipermail/connman/2012-September/011232.html >>>> >>>> However, Eric's patch still causes tethering problems to me. >>> >>> >>> Let me recap a bit. Artem is using connman, which sets up the wifi >>> interface as part of a bridge. It runs wpa_supplicant to create an AP >>> (only AP and mesh mode interfaces can be bridged anyway). >>> >>> >>> Eric, you said: >>> >>>> I would say some part of the stack assumes a header (I dont know wich >>>> one ?) is pulled in skb->head/data, and thats a bug. >>>> >>>> Always use pskb_may_pull(skb, XXX) to make sure you can access XXX >>>> bytes in skb->data >>> >>> I thought we'd figure out which part of the stack assumes a header, so I >>> asked Artem to test a one-line patch which adds "skb_linearize()" before >>> "netif_receive_skb()" in mac80211. This makes it work, but I'm not sure >>> where after that the bad assumption might be. >>> >>> johannes >>> -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-09-20 at 14:45 +0200, Eric Dumazet wrote: > I guess you only need to make sure 14 bytes of ethernet header are > available before eth_type_trans(skb, dev); > > diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c > index 61c621e..ffe5f84 100644 > --- a/net/mac80211/rx.c > +++ b/net/mac80211/rx.c > @@ -1795,9 +1795,13 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx) > > if (skb) { > /* deliver to local stack */ > - skb->protocol = eth_type_trans(skb, dev); > - memset(skb->cb, 0, sizeof(skb->cb)); > - netif_receive_skb(skb); > + if (pskb_may_pull(skb, sizeof(struct ethhdr))) { > + skb->protocol = eth_type_trans(skb, dev); > + memset(skb->cb, 0, sizeof(skb->cb)); > + netif_receive_skb(skb); > + } else { > + kfree_skb(skb); > + } > } > } Yeah I was looking at the same code just now. However, we had actually inserted the skb_linearize() *after* eth_type_trans(), so I'm confused. Maybe it still works, more or less by accident? johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Or its a buggy protocol ? IP/UDP/TCP definitely works, but maybe another protocol assumes its header is in skb->head On Thu, Sep 20, 2012 at 2:47 PM, Johannes Berg <johannes@sipsolutions.net> wrote: > On Thu, 2012-09-20 at 14:45 +0200, Eric Dumazet wrote: >> I guess you only need to make sure 14 bytes of ethernet header are >> available before eth_type_trans(skb, dev); >> >> diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c >> index 61c621e..ffe5f84 100644 >> --- a/net/mac80211/rx.c >> +++ b/net/mac80211/rx.c >> @@ -1795,9 +1795,13 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx) >> >> if (skb) { >> /* deliver to local stack */ >> - skb->protocol = eth_type_trans(skb, dev); >> - memset(skb->cb, 0, sizeof(skb->cb)); >> - netif_receive_skb(skb); >> + if (pskb_may_pull(skb, sizeof(struct ethhdr))) { >> + skb->protocol = eth_type_trans(skb, dev); >> + memset(skb->cb, 0, sizeof(skb->cb)); >> + netif_receive_skb(skb); >> + } else { >> + kfree_skb(skb); >> + } >> } >> } > > Yeah I was looking at the same code just now. However, we had actually > inserted the skb_linearize() *after* eth_type_trans(), so I'm confused. > Maybe it still works, more or less by accident? > > johannes > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-09-20 at 14:46 +0200, Eric Dumazet wrote: > Or its the lines with CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS ? > > What arch is it ? x86 johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-09-20 at 14:48 +0200, Eric Dumazet wrote: > Or its a buggy protocol ? > > IP/UDP/TCP definitely works, but maybe another protocol assumes its > header is in skb->head It could be, I think it failed either on EAPOL (which is just userspace registering a protocol socket) or DHCP (same?) johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
So its using a RAW socket ? On Thu, Sep 20, 2012 at 2:50 PM, Johannes Berg <johannes@sipsolutions.net> wrote: > On Thu, 2012-09-20 at 14:48 +0200, Eric Dumazet wrote: >> Or its a buggy protocol ? >> >> IP/UDP/TCP definitely works, but maybe another protocol assumes its >> header is in skb->head > > It could be, I think it failed either on EAPOL (which is just userspace > registering a protocol socket) or DHCP (same?) > > johannes > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-09-20 at 14:47 +0200, Johannes Berg wrote: > > if (skb) { > > /* deliver to local stack */ > > - skb->protocol = eth_type_trans(skb, dev); > > - memset(skb->cb, 0, sizeof(skb->cb)); > > - netif_receive_skb(skb); > > + if (pskb_may_pull(skb, sizeof(struct ethhdr))) { > > + skb->protocol = eth_type_trans(skb, dev); > > + memset(skb->cb, 0, sizeof(skb->cb)); > > + netif_receive_skb(skb); > > + } else { > > + kfree_skb(skb); > > + } > > } > > } > > Yeah I was looking at the same code just now. However, we had actually > inserted the skb_linearize() *after* eth_type_trans(), so I'm confused. Ok actually, by the time we get here the ethernet header must be in the skb head because we construct it from the 802.11 and llc/snap header. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-09-20 at 14:51 +0200, Eric Dumazet wrote: > So its using a RAW socket ? Yes: socket(PF_PACKET, SOCK_RAW, htons(ETH_P_EAPOL)) johannes > On Thu, Sep 20, 2012 at 2:50 PM, Johannes Berg > <johannes@sipsolutions.net> wrote: > > On Thu, 2012-09-20 at 14:48 +0200, Eric Dumazet wrote: > >> Or its a buggy protocol ? > >> > >> IP/UDP/TCP definitely works, but maybe another protocol assumes its > >> header is in skb->head > > > > It could be, I think it failed either on EAPOL (which is just userspace > > registering a protocol socket) or DHCP (same?) > > > > johannes > > > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 61c621e..ffe5f84 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1795,9 +1795,13 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx) if (skb) { /* deliver to local stack */ - skb->protocol = eth_type_trans(skb, dev); - memset(skb->cb, 0, sizeof(skb->cb)); - netif_receive_skb(skb); + if (pskb_may_pull(skb, sizeof(struct ethhdr))) { + skb->protocol = eth_type_trans(skb, dev); + memset(skb->cb, 0, sizeof(skb->cb)); + netif_receive_skb(skb); + } else { + kfree_skb(skb); + } } }