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 BD880C282D7 for ; Wed, 30 Jan 2019 19:48:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E51A2084C for ; Wed, 30 Jan 2019 19:48:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RS2EoOs5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732830AbfA3Ts3 (ORCPT ); Wed, 30 Jan 2019 14:48:29 -0500 Received: from mail-it1-f201.google.com ([209.85.166.201]:50587 "EHLO mail-it1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727760AbfA3Ts3 (ORCPT ); Wed, 30 Jan 2019 14:48:29 -0500 Received: by mail-it1-f201.google.com with SMTP id p66so127508itc.0 for ; Wed, 30 Jan 2019 11:48:28 -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=zzaR14K4VzcAFPicenemY619M2AaPc9K15z75YS6cOA=; b=RS2EoOs5slv2riYAVE122zkwVlPoHUB5Z4URVMpf99VG7NvNYmKt89J/3vqY2zBFoU Shh00gOaSPceQRsM4Jc3+8Hc5yUc+F3A/Hj0e5mpGxE+xIqr3P2Wg8sWzZzeQ33Z+uDZ P0o1TggFWeEQsIDSzkUgSRtsBXAId4qybCiKOu2bMU4BSd8V4j+9YtIps2LXT7wTe6Nb 64AY4uxXwhUwfEfm4i2CJ4Y0psXjaqvTNlTDK5ZiIimbBB86uqUMpga8ij2irtlHDhVN mF0CGvmceNBe52oicioIBVeZPXdV9yshPS9ETQuAQiQEWvk9TLj5YwWZax/aEtw9wWf9 60qg== 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=zzaR14K4VzcAFPicenemY619M2AaPc9K15z75YS6cOA=; b=Hr+LClJotVZ/jDoysF+LAlLSfahFayDARwa4TtCsNst/fYZ2WJbPDAE15Uq8BjbnjC PuhzSrtLXEOnIEXXPX2iCMcqo+fB9VSAg5Npmz13Nni6gxhsRpBisFkPPGCOtXSuf6YY X6uqZ704fHEUxzJt5b4S5uIKqxxfg23dWtAjH/R2bPidCQclwnyvEgNHTpZ42aMpVZj6 YWLDajA+DV0ISTb6E2SEVFzPQFrxS5cHIjTOTCKrxWnhmBYsQR3nwNOHHfc0KRg3ZhJc qxQ3BUnjhqQQLy2YdUnovt+kRaZJNp+EOV41NH3ryUS0NwRHtVqxagZy33YklCBN+cyH 5lHw== X-Gm-Message-State: AHQUAuZ1mBYipU3ki5m79F5mymK/pBNFNLDPKgEjGSUv29Vi75DTiuKQ 5KZ1nLlgyjzq/Z0t5wSTQoAoaust X-Google-Smtp-Source: AHgI3IbFT0KF1FAn2tXMi8n8rVPV/bHMYB7OR6wRnW5zO1k9tOocnoadpBTbY/GbAOZku14FOvwfi7eR X-Received: by 2002:a24:4ac3:: with SMTP id k186mr7219841itb.37.1548877707899; Wed, 30 Jan 2019 11:48:27 -0800 (PST) Date: Wed, 30 Jan 2019 11:48:08 -0800 In-Reply-To: <20190130194811.239760-1-posk@google.com> Message-Id: <20190130194811.239760-3-posk@google.com> Mime-Version: 1.0 References: <20190130194811.239760-1-posk@google.com> X-Mailer: git-send-email 2.20.1.495.gaa96b0ce6b-goog Subject: [PATCH bpf-next v4 2/5] 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 , 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 This patch implements 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). Signed-off-by: Peter Oskolkov --- include/net/lwtunnel.h | 3 +++ net/core/filter.c | 3 ++- net/core/lwt_bpf.c | 59 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 64 insertions(+), 1 deletion(-) diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h index 33fd9ba7e0e5..f0973eca8036 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) { @@ -138,6 +140,7 @@ static inline void lwtunnel_set_redirect(struct dst_entry *dst) dst->input = lwtunnel_input; } } + #else static inline void lwtstate_free(struct lwtunnel_state *lws) diff --git a/net/core/filter.c b/net/core/filter.c index 27d3fbe4b77b..de6bd4b4e0a3 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 @@ -4804,7 +4805,7 @@ 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); } BPF_CALL_4(bpf_lwt_in_push_encap, struct sk_buff *, skb, u32, type, void *, hdr, diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c index a648568c5e8f..6a6e9acab73d 100644 --- a/net/core/lwt_bpf.c +++ b/net/core/lwt_bpf.c @@ -390,6 +390,65 @@ static const struct lwtunnel_encap_ops bpf_encap_ops = { .owner = THIS_MODULE, }; +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); + + if (ipv4) { + skb->protocol = htons(ETH_P_IP); + iph = ip_hdr(skb); + if (iph->ihl * 4 < len) + skb_set_transport_header(skb, iph->ihl * 4); + + if (!iph->check) + iph->check = ip_fast_csum((unsigned char *)iph, + iph->ihl); + } else { + skb->protocol = htons(ETH_P_IPV6); + if (sizeof(struct ipv6hdr) < len) + skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + } + + return 0; +} + static int __init bpf_lwt_init(void) { return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF); -- 2.20.1.495.gaa96b0ce6b-goog