From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AA4DC282C4 for ; Tue, 12 Feb 2019 17:33:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0424E20821 for ; Tue, 12 Feb 2019 17:33:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ijCEQYU6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730955AbfBLRdC (ORCPT ); Tue, 12 Feb 2019 12:33:02 -0500 Received: from mail-pg1-f202.google.com ([209.85.215.202]:54707 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728066AbfBLRdB (ORCPT ); Tue, 12 Feb 2019 12:33:01 -0500 Received: by mail-pg1-f202.google.com with SMTP id 2so2530936pgg.21 for ; Tue, 12 Feb 2019 09:33:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=qqz5RegrCN8L1NVjilJsx8Ak84pUlSYYkGI27Z9WhK8=; b=ijCEQYU6KzCvhRAglNPJAd6gzN5I57E9DPoBjkEN53NDjxOVGGXqN5+KsNwuNXcPE1 Tz6EVbLW56a2bp9mT+NOYS2DkSHM+gQg1M9MeOF7naUMYO+8Ro60Gk93O6btud2HTf/E epfkPjvmi+qgBJnGhg+6NXOBPZLVfQlisso35+B4TjhiQ5tM3Q2Lm+QwWlP1PO7doovP f9WPYp8QX6LGkRh8BdCYbi6x+hLDKG4Ktn6S+H9lcAADlKlWOnEHnU6qSMjhDCF4xN6z f2+oBFXG7aF+Be9Cny3/VFS9889RaKaKa/hTEmu03KyWnGM1NUBcLVdNtxhiICaMbnhN mh3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=qqz5RegrCN8L1NVjilJsx8Ak84pUlSYYkGI27Z9WhK8=; b=au2IbX3pOYZ2qVeQ0Xea2f5ZC5MEqLoT/Qe5g+STBMGLAigEqxK2bdYQoyw8eqoW6X AoHKXP45aTVhY8m1NeJNh/CllaFhBKf4hp5XkYl5APexgxnvEGSZtpCfb9bA8Eys+smr ckKAxgNYvkVjSv2BKduJw5sZI2Z8ZZ6KurpwV/RsFb8e5wvbLiAdKZ3AL7q1fagwV6NL zjTlfeK0ZyMluPhoRss3L7jc4tpDkqhw2LjRUG6O8JCmGWEbaF6zer4hXBczTg6z9rNl OuEWbiTkrQBrFU/9t8ynT/ooIDdlOg+AgDO2kYJj0h3pAY6Kaz+/WELAG24BglJnWH/+ TWug== X-Gm-Message-State: AHQUAuZdNZAbc6MzTVNjXEW0+oby9Gy+4cIfjiWfvZjQUBfZmQV+PbKn 8G5WLLABeAwP+whbbQhG8Gi09rtb X-Google-Smtp-Source: AHgI3IbYIxJqX3Lb4fymfqS3/AR6dS6kV3tx5oZrnSCZHeIXEUrVAZ2GOxQen/tKjB/DsBbgew13wPe7 X-Received: by 2002:a63:fa02:: with SMTP id y2mr1793387pgh.12.1549992780472; Tue, 12 Feb 2019 09:33:00 -0800 (PST) Date: Tue, 12 Feb 2019 09:32:42 -0800 In-Reply-To: <20190212173247.121342-1-posk@google.com> Message-Id: <20190212173247.121342-3-posk@google.com> Mime-Version: 1.0 References: <20190212173247.121342-1-posk@google.com> X-Mailer: git-send-email 2.20.1.791.gb4d0f1c61a-goog Subject: [PATCH bpf-next v10 2/7] bpf: implement BPF_LWT_ENCAP_IP mode in bpf_lwt_push_encap From: Peter Oskolkov To: Alexei Starovoitov , Daniel Borkmann , netdev@vger.kernel.org Cc: Peter Oskolkov , David Ahern , Willem de Bruijn , Peter Oskolkov Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Implement BPF_LWT_ENCAP_IP mode in bpf_lwt_push_encap BPF helper. It enables BPF programs (specifically, BPF_PROG_TYPE_LWT_IN and BPF_PROG_TYPE_LWT_XMIT prog types) to add IP encapsulation headers to packets (e.g. IP/GRE, GUE, IPIP). This is useful when thousands of different short-lived flows should be encapped, each with different and dynamically determined destination. Although lwtunnels can be used in some of these scenarios, the ability to dynamically generate encap headers adds more flexibility, e.g. when routing depends on the state of the host (reflected in global bpf maps). v7 changes: - added a call skb_clear_hash(); - removed calls to skb_set_transport_header(); - refuse to encap GSO-enabled packets. v8 changes: - fix build errors when LWT is not enabled. Note: the next patch in the patchset with deal with GSO-enabled packets, which are currently rejected at encapping attempt. Signed-off-by: Peter Oskolkov --- include/net/lwtunnel.h | 2 ++ net/core/filter.c | 3 +- net/core/lwt_bpf.c | 65 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 69 insertions(+), 1 deletion(-) diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h index 33fd9ba7e0e5..671113bcb2cc 100644 --- a/include/net/lwtunnel.h +++ b/include/net/lwtunnel.h @@ -126,6 +126,8 @@ int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b); int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb); int lwtunnel_input(struct sk_buff *skb); int lwtunnel_xmit(struct sk_buff *skb); +int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len, + bool ingress); static inline void lwtunnel_set_redirect(struct dst_entry *dst) { diff --git a/net/core/filter.c b/net/core/filter.c index 12c88c21b6b8..a78deb2656e1 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -73,6 +73,7 @@ #include #include #include +#include /** * sk_filter_trim_cap - run a packet through a socket filter @@ -4819,7 +4820,7 @@ static int bpf_push_seg6_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len static int bpf_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len, bool ingress) { - return -EINVAL; /* Implemented in the next patch. */ + return bpf_lwt_push_ip_encap(skb, hdr, len, ingress); } #endif diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c index a648568c5e8f..e5a9850d9f48 100644 --- a/net/core/lwt_bpf.c +++ b/net/core/lwt_bpf.c @@ -390,6 +390,71 @@ static const struct lwtunnel_encap_ops bpf_encap_ops = { .owner = THIS_MODULE, }; +static int handle_gso_encap(struct sk_buff *skb, bool ipv4, int encap_len) +{ + /* Handling of GSO-enabled packets is added in the next patch. */ + return -EOPNOTSUPP; +} + +int bpf_lwt_push_ip_encap(struct sk_buff *skb, void *hdr, u32 len, bool ingress) +{ + struct iphdr *iph; + bool ipv4; + int err; + + if (unlikely(len < sizeof(struct iphdr) || len > LWT_BPF_MAX_HEADROOM)) + return -EINVAL; + + /* validate protocol and length */ + iph = (struct iphdr *)hdr; + if (iph->version == 4) { + ipv4 = true; + if (unlikely(len < iph->ihl * 4)) + return -EINVAL; + } else if (iph->version == 6) { + ipv4 = false; + if (unlikely(len < sizeof(struct ipv6hdr))) + return -EINVAL; + } else { + return -EINVAL; + } + + if (ingress) + err = skb_cow_head(skb, len + skb->mac_len); + else + err = skb_cow_head(skb, + len + LL_RESERVED_SPACE(skb_dst(skb)->dev)); + if (unlikely(err)) + return err; + + /* push the encap headers and fix pointers */ + skb_reset_inner_headers(skb); + skb->encapsulation = 1; + skb_push(skb, len); + if (ingress) + skb_postpush_rcsum(skb, iph, len); + skb_reset_network_header(skb); + memcpy(skb_network_header(skb), hdr, len); + bpf_compute_data_pointers(skb); + skb_clear_hash(skb); + + if (ipv4) { + skb->protocol = htons(ETH_P_IP); + iph = ip_hdr(skb); + + if (!iph->check) + iph->check = ip_fast_csum((unsigned char *)iph, + iph->ihl); + } else { + skb->protocol = htons(ETH_P_IPV6); + } + + if (skb_is_gso(skb)) + return handle_gso_encap(skb, ipv4, len); + + return 0; +} + static int __init bpf_lwt_init(void) { return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF); -- 2.20.1.791.gb4d0f1c61a-goog