From 4c9451ed94087abf0e45835f133e0fa44b809f96 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Sun, 9 Nov 2014 18:50:10 +0200 Subject: [PATCH] mac80211: factor out 802.11 header building code Factor out the 802.11 header building code from the xmit function to be able to use it separately in a later commit. While at it, fix up some documentation. Signed-off-by: Johannes Berg Signed-off-by: Arik Nemtsov Signed-off-by: Johannes Berg --- net/mac80211/tx.c | 144 +++++++++++++++++++++++++++++----------------- 1 file changed, 92 insertions(+), 52 deletions(-) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index c4a5494c2ac6..55d69fda4c6a 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1784,24 +1784,26 @@ static void ieee80211_tx_latency_start_msrmnt(struct ieee80211_local *local, } /** - * __ieee80211_subif_start_xmit - netif start_xmit function for Ethernet-type - * subinterfaces (wlan#, WDS, and VLAN interfaces) - * @skb: packet to be sent - * @dev: incoming interface + * ieee80211_build_hdr - build 802.11 header in the given frame + * @sdata: virtual interface to build the header for + * @skb: the skb to build the header in * @info_flags: skb flags to set * - * On failure skb will be freed. + * This function takes the skb with 802.3 header and reformats the header to + * the appropriate IEEE 802.11 header based on which interface the packet is + * being transmitted on. + * + * Note that this function also takes care of the TX status request and + * potential unsharing of the SKB - this needs to be interleaved with the + * header building. + * + * The function requires the read-side RCU lock held * - * This function takes in an Ethernet header and encapsulates it with suitable - * IEEE 802.11 header based on which interface the packet is coming in. The - * encapsulated packet will then be passed to master interface, wlan#.11, for - * transmission (through low-level driver). + * Returns: the (possibly reallocated) skb or an ERR_PTR() code */ -void __ieee80211_subif_start_xmit(struct sk_buff *skb, - struct net_device *dev, - u32 info_flags) +static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata, + struct sk_buff *skb, u32 info_flags) { - struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); struct ieee80211_local *local = sdata->local; struct ieee80211_tx_info *info; int head_need; @@ -1821,20 +1823,13 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, struct ieee80211_chanctx_conf *chanctx_conf; struct ieee80211_sub_if_data *ap_sdata; enum ieee80211_band band; - - if (unlikely(skb->len < ETH_HLEN)) - goto fail; + int ret; /* convert Ethernet header to proper 802.11 header (based on * operation mode) */ ethertype = (skb->data[12] << 8) | skb->data[13]; fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA); - rcu_read_lock(); - - /* Measure frame arrival for Tx latency statistics calculation */ - ieee80211_tx_latency_start_msrmnt(local, skb); - switch (sdata->vif.type) { case NL80211_IFTYPE_AP_VLAN: sta = rcu_dereference(sdata->u.vlan.sta); @@ -1852,8 +1847,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, ap_sdata = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap); chanctx_conf = rcu_dereference(ap_sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; + if (!chanctx_conf) { + ret = -ENOTCONN; + goto free; + } band = chanctx_conf->def.chan->band; if (sta) break; @@ -1861,8 +1858,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, case NL80211_IFTYPE_AP: if (sdata->vif.type == NL80211_IFTYPE_AP) chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; + if (!chanctx_conf) { + ret = -ENOTCONN; + goto free; + } fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS); /* DA BSSID SA */ memcpy(hdr.addr1, skb->data, ETH_ALEN); @@ -1949,8 +1948,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, } chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; + if (!chanctx_conf) { + ret = -ENOTCONN; + goto free; + } band = chanctx_conf->def.chan->band; break; #endif @@ -1980,8 +1981,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, * of a link teardown after a TDLS sta is removed due to being * unreachable. */ - if (tdls_peer && !tdls_auth && !tdls_setup_frame) - goto fail_rcu; + if (tdls_peer && !tdls_auth && !tdls_setup_frame) { + ret = -EINVAL; + goto free; + } /* send direct packets to authorized TDLS peers */ if (tdls_peer && tdls_auth) { @@ -2009,8 +2012,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, hdrlen = 24; } chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; + if (!chanctx_conf) { + ret = -ENOTCONN; + goto free; + } band = chanctx_conf->def.chan->band; break; case NL80211_IFTYPE_OCB: @@ -2020,8 +2025,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, eth_broadcast_addr(hdr.addr3); hdrlen = 24; chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; + if (!chanctx_conf) { + ret = -ENOTCONN; + goto free; + } band = chanctx_conf->def.chan->band; break; case NL80211_IFTYPE_ADHOC: @@ -2031,12 +2038,15 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, memcpy(hdr.addr3, sdata->u.ibss.bssid, ETH_ALEN); hdrlen = 24; chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (!chanctx_conf) - goto fail_rcu; + if (!chanctx_conf) { + ret = -ENOTCONN; + goto free; + } band = chanctx_conf->def.chan->band; break; default: - goto fail_rcu; + ret = -EINVAL; + goto free; } /* @@ -2074,12 +2084,13 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, !ether_addr_equal(sdata->vif.addr, skb->data + ETH_ALEN)))) { #ifdef CONFIG_MAC80211_VERBOSE_DEBUG net_info_ratelimited("%s: dropped frame to %pM (unauthorized port)\n", - dev->name, hdr.addr1); + sdata->name, hdr.addr1); #endif I802_DEBUG_INC(local->tx_handlers_drop_unauth_port); - goto fail_rcu; + ret = -EPERM; + goto free; } if (unlikely(!multicast && skb->sk && @@ -2116,8 +2127,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, skb = skb_clone(skb, GFP_ATOMIC); kfree_skb(tmp_skb); - if (!skb) - goto fail_rcu; + if (!skb) { + ret = -ENOMEM; + goto free; + } } hdr.frame_control = fc; @@ -2166,7 +2179,7 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, if (ieee80211_skb_resize(sdata, skb, head_need, true)) { ieee80211_free_txskb(&local->hw, skb); skb = NULL; - goto fail_rcu; + return ERR_PTR(-ENOMEM); } } @@ -2200,9 +2213,6 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, nh_pos += hdrlen; h_pos += hdrlen; - dev->stats.tx_packets++; - dev->stats.tx_bytes += skb->len; - /* Update skb pointers to various headers since this modified frame * is going to go through Linux networking code that may potentially * need things like pointer to IP header. */ @@ -2213,23 +2223,53 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb, info = IEEE80211_SKB_CB(skb); memset(info, 0, sizeof(*info)); - dev->trans_start = jiffies; - info->flags = info_flags; info->ack_frame_id = info_id; info->band = band; - ieee80211_xmit(sdata, skb); - rcu_read_unlock(); + return skb; + free: + kfree_skb(skb); + return ERR_PTR(ret); +} + +void __ieee80211_subif_start_xmit(struct sk_buff *skb, + struct net_device *dev, + u32 info_flags) +{ + struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); + struct ieee80211_local *local = sdata->local; + + if (unlikely(skb->len < ETH_HLEN)) { + kfree_skb(skb); + return; + } + + rcu_read_lock(); + + /* Measure frame arrival for Tx latency statistics calculation */ + ieee80211_tx_latency_start_msrmnt(local, skb); + + skb = ieee80211_build_hdr(sdata, skb, info_flags); + if (IS_ERR(skb)) + goto out; - return; + dev->stats.tx_packets++; + dev->stats.tx_bytes += skb->len; + dev->trans_start = jiffies; - fail_rcu: + ieee80211_xmit(sdata, skb); + out: rcu_read_unlock(); - fail: - dev_kfree_skb(skb); } +/** + * ieee80211_subif_start_xmit - netif start_xmit function for 802.3 vifs + * @skb: packet to be sent + * @dev: incoming interface + * + * On failure skb will be freed. + */ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb, struct net_device *dev) { -- 2.39.5