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[213.102.90.208]) by smtp.gmail.com with ESMTPSA id h20sm2309249lfc.239.2021.01.19.07.50.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Jan 2021 07:50:23 -0800 (PST) From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= To: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , magnus.karlsson@intel.com, maciej.fijalkowski@intel.com, kuba@kernel.org, jonathan.lemon@gmail.com, maximmi@nvidia.com, davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com, ciara.loftus@intel.com, weqaar.a.janjua@intel.com Subject: [PATCH bpf-next v2 1/8] xdp: restructure redirect actions Date: Tue, 19 Jan 2021 16:50:06 +0100 Message-Id: <20210119155013.154808-2-bjorn.topel@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210119155013.154808-1-bjorn.topel@gmail.com> References: <20210119155013.154808-1-bjorn.topel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Björn Töpel The XDP_REDIRECT implementations for maps and non-maps are fairly similar, but obviously need to take different code paths depending on if the target is using a map or not. Today, the redirect targets for XDP either uses a map, or is based on ifindex. Future commits will introduce yet another redirect target via the a new helper, bpf_redirect_xsk(). To pave the way for that, we introduce an explicit redirect type to bpf_redirect_info. This makes the code easier to follow, and makes it easier to add new redirect targets. Further, using an explicit type in bpf_redirect_info has a slight positive performance impact by avoiding a pointer indirection for the map type lookup, and instead use the hot cacheline for bpf_redirect_info. The bpf_redirect_info flags member is not used by XDP, and not read/written any more. The map member is only written to when required/used, and not unconditionally. Reviewed-by: Maciej Fijalkowski Signed-off-by: Björn Töpel --- include/linux/filter.h | 9 ++ include/trace/events/xdp.h | 46 +++++++---- net/core/filter.c | 164 ++++++++++++++++++------------------- 3 files changed, 117 insertions(+), 102 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 7fdce5407214..5fc336a271c2 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -637,10 +637,19 @@ struct bpf_redirect_info { u32 tgt_index; void *tgt_value; struct bpf_map *map; + u32 tgt_type; u32 kern_flags; struct bpf_nh_params nh; }; +enum xdp_redirect_type { + XDP_REDIR_UNSET, + XDP_REDIR_DEV_IFINDEX, + XDP_REDIR_DEV_MAP, + XDP_REDIR_CPU_MAP, + XDP_REDIR_XSK_MAP, +}; + DECLARE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info); /* flags for bpf_redirect_info kern_flags */ diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h index 76a97176ab81..0e17b9a74f28 100644 --- a/include/trace/events/xdp.h +++ b/include/trace/events/xdp.h @@ -96,9 +96,10 @@ DECLARE_EVENT_CLASS(xdp_redirect_template, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, const void *tgt, int err, - const struct bpf_map *map, u32 index), + enum xdp_redirect_type type, + const struct bpf_redirect_info *ri), - TP_ARGS(dev, xdp, tgt, err, map, index), + TP_ARGS(dev, xdp, tgt, err, type, ri), TP_STRUCT__entry( __field(int, prog_id) @@ -111,12 +112,19 @@ DECLARE_EVENT_CLASS(xdp_redirect_template, ), TP_fast_assign( + struct bpf_map *map = NULL; + u32 index = ri->tgt_index; + + if (type == XDP_REDIR_DEV_MAP || type == XDP_REDIR_CPU_MAP || + type == XDP_REDIR_XSK_MAP) + map = READ_ONCE(ri->map); + __entry->prog_id = xdp->aux->id; __entry->act = XDP_REDIRECT; __entry->ifindex = dev->ifindex; __entry->err = err; __entry->to_ifindex = map ? devmap_ifindex(tgt, map) : - index; + (u32)(long)tgt; __entry->map_id = map ? map->id : 0; __entry->map_index = map ? index : 0; ), @@ -133,45 +141,49 @@ DEFINE_EVENT(xdp_redirect_template, xdp_redirect, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, const void *tgt, int err, - const struct bpf_map *map, u32 index), - TP_ARGS(dev, xdp, tgt, err, map, index) + enum xdp_redirect_type type, + const struct bpf_redirect_info *ri), + TP_ARGS(dev, xdp, tgt, err, type, ri) ); DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, const void *tgt, int err, - const struct bpf_map *map, u32 index), - TP_ARGS(dev, xdp, tgt, err, map, index) + enum xdp_redirect_type type, + const struct bpf_redirect_info *ri), + TP_ARGS(dev, xdp, tgt, err, type, ri) ); #define _trace_xdp_redirect(dev, xdp, to) \ - trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to) + trace_xdp_redirect(dev, xdp, NULL, 0, XDP_REDIR_DEV_IFINDEX, NULL) #define _trace_xdp_redirect_err(dev, xdp, to, err) \ - trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to) + trace_xdp_redirect_err(dev, xdp, NULL, err, XDP_REDIR_DEV_IFINDEX, NULL) -#define _trace_xdp_redirect_map(dev, xdp, to, map, index) \ - trace_xdp_redirect(dev, xdp, to, 0, map, index) +#define _trace_xdp_redirect_map(dev, xdp, to, type, ri) \ + trace_xdp_redirect(dev, xdp, to, 0, type, ri) -#define _trace_xdp_redirect_map_err(dev, xdp, to, map, index, err) \ - trace_xdp_redirect_err(dev, xdp, to, err, map, index) +#define _trace_xdp_redirect_map_err(dev, xdp, to, type, ri, err) \ + trace_xdp_redirect_err(dev, xdp, to, err, type, ri) /* not used anymore, but kept around so as not to break old programs */ DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, const void *tgt, int err, - const struct bpf_map *map, u32 index), - TP_ARGS(dev, xdp, tgt, err, map, index) + enum xdp_redirect_type type, + const struct bpf_redirect_info *ri), + TP_ARGS(dev, xdp, tgt, err, type, ri) ); DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map_err, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, const void *tgt, int err, - const struct bpf_map *map, u32 index), - TP_ARGS(dev, xdp, tgt, err, map, index) + enum xdp_redirect_type type, + const struct bpf_redirect_info *ri), + TP_ARGS(dev, xdp, tgt, err, type, ri) ); TRACE_EVENT(xdp_cpumap_kthread, diff --git a/net/core/filter.c b/net/core/filter.c index 9ab94e90d660..5f31e21be531 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3923,23 +3923,6 @@ static const struct bpf_func_proto bpf_xdp_adjust_meta_proto = { .arg2_type = ARG_ANYTHING, }; -static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd, - struct bpf_map *map, struct xdp_buff *xdp) -{ - switch (map->map_type) { - case BPF_MAP_TYPE_DEVMAP: - case BPF_MAP_TYPE_DEVMAP_HASH: - return dev_map_enqueue(fwd, xdp, dev_rx); - case BPF_MAP_TYPE_CPUMAP: - return cpu_map_enqueue(fwd, xdp, dev_rx); - case BPF_MAP_TYPE_XSKMAP: - return __xsk_map_redirect(fwd, xdp); - default: - return -EBADRQC; - } - return 0; -} - void xdp_do_flush(void) { __dev_flush(); @@ -3948,22 +3931,6 @@ void xdp_do_flush(void) } EXPORT_SYMBOL_GPL(xdp_do_flush); -static inline void *__xdp_map_lookup_elem(struct bpf_map *map, u32 index) -{ - switch (map->map_type) { - case BPF_MAP_TYPE_DEVMAP: - return __dev_map_lookup_elem(map, index); - case BPF_MAP_TYPE_DEVMAP_HASH: - return __dev_map_hash_lookup_elem(map, index); - case BPF_MAP_TYPE_CPUMAP: - return __cpu_map_lookup_elem(map, index); - case BPF_MAP_TYPE_XSKMAP: - return __xsk_map_lookup_elem(map, index); - default: - return NULL; - } -} - void bpf_clear_redirect_map(struct bpf_map *map) { struct bpf_redirect_info *ri; @@ -3985,34 +3952,42 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, struct bpf_prog *xdp_prog) { struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); - struct bpf_map *map = READ_ONCE(ri->map); - u32 index = ri->tgt_index; + enum xdp_redirect_type type = ri->tgt_type; void *fwd = ri->tgt_value; int err; - ri->tgt_index = 0; + ri->tgt_type = XDP_REDIR_UNSET; ri->tgt_value = NULL; - WRITE_ONCE(ri->map, NULL); - if (unlikely(!map)) { - fwd = dev_get_by_index_rcu(dev_net(dev), index); + switch (type) { + case XDP_REDIR_DEV_IFINDEX: + fwd = dev_get_by_index_rcu(dev_net(dev), (u32)(long)fwd); if (unlikely(!fwd)) { err = -EINVAL; - goto err; + break; } - err = dev_xdp_enqueue(fwd, xdp, dev); - } else { - err = __bpf_tx_xdp_map(dev, fwd, map, xdp); + break; + case XDP_REDIR_DEV_MAP: + err = dev_map_enqueue(fwd, xdp, dev); + break; + case XDP_REDIR_CPU_MAP: + err = cpu_map_enqueue(fwd, xdp, dev); + break; + case XDP_REDIR_XSK_MAP: + err = __xsk_map_redirect(fwd, xdp); + break; + default: + err = -EBADRQC; } if (unlikely(err)) goto err; - _trace_xdp_redirect_map(dev, xdp_prog, fwd, map, index); + _trace_xdp_redirect_map(dev, xdp_prog, fwd, type, ri); return 0; err: - _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err); + _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, type, ri, err); return err; } EXPORT_SYMBOL_GPL(xdp_do_redirect); @@ -4021,41 +3996,40 @@ static int xdp_do_generic_redirect_map(struct net_device *dev, struct sk_buff *skb, struct xdp_buff *xdp, struct bpf_prog *xdp_prog, - struct bpf_map *map) + void *fwd, + enum xdp_redirect_type type) { struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); - u32 index = ri->tgt_index; - void *fwd = ri->tgt_value; - int err = 0; - - ri->tgt_index = 0; - ri->tgt_value = NULL; - WRITE_ONCE(ri->map, NULL); + int err; - if (map->map_type == BPF_MAP_TYPE_DEVMAP || - map->map_type == BPF_MAP_TYPE_DEVMAP_HASH) { + switch (type) { + case XDP_REDIR_DEV_MAP: { struct bpf_dtab_netdev *dst = fwd; err = dev_map_generic_redirect(dst, skb, xdp_prog); if (unlikely(err)) goto err; - } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) { + break; + } + case XDP_REDIR_XSK_MAP: { struct xdp_sock *xs = fwd; err = xsk_generic_rcv(xs, xdp); if (err) goto err; consume_skb(skb); - } else { + break; + } + default: /* TODO: Handle BPF_MAP_TYPE_CPUMAP */ err = -EBADRQC; goto err; } - _trace_xdp_redirect_map(dev, xdp_prog, fwd, map, index); + _trace_xdp_redirect_map(dev, xdp_prog, fwd, type, ri); return 0; err: - _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err); + _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, type, ri, err); return err; } @@ -4063,29 +4037,31 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb, struct xdp_buff *xdp, struct bpf_prog *xdp_prog) { struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); - struct bpf_map *map = READ_ONCE(ri->map); - u32 index = ri->tgt_index; - struct net_device *fwd; + enum xdp_redirect_type type = ri->tgt_type; + void *fwd = ri->tgt_value; int err = 0; - if (map) - return xdp_do_generic_redirect_map(dev, skb, xdp, xdp_prog, - map); - ri->tgt_index = 0; - fwd = dev_get_by_index_rcu(dev_net(dev), index); - if (unlikely(!fwd)) { - err = -EINVAL; - goto err; - } + ri->tgt_type = XDP_REDIR_UNSET; + ri->tgt_value = NULL; - err = xdp_ok_fwd_dev(fwd, skb->len); - if (unlikely(err)) - goto err; + if (type == XDP_REDIR_DEV_IFINDEX) { + fwd = dev_get_by_index_rcu(dev_net(dev), (u32)(long)fwd); + if (unlikely(!fwd)) { + err = -EINVAL; + goto err; + } - skb->dev = fwd; - _trace_xdp_redirect(dev, xdp_prog, index); - generic_xdp_tx(skb, xdp_prog); - return 0; + err = xdp_ok_fwd_dev(fwd, skb->len); + if (unlikely(err)) + goto err; + + skb->dev = fwd; + _trace_xdp_redirect(dev, xdp_prog, index); + generic_xdp_tx(skb, xdp_prog); + return 0; + } + + return xdp_do_generic_redirect_map(dev, skb, xdp, xdp_prog, fwd, type); err: _trace_xdp_redirect_err(dev, xdp_prog, index, err); return err; @@ -4098,10 +4074,9 @@ BPF_CALL_2(bpf_xdp_redirect, u32, ifindex, u64, flags) if (unlikely(flags)) return XDP_ABORTED; - ri->flags = flags; - ri->tgt_index = ifindex; - ri->tgt_value = NULL; - WRITE_ONCE(ri->map, NULL); + ri->tgt_type = XDP_REDIR_DEV_IFINDEX; + ri->tgt_index = 0; + ri->tgt_value = (void *)(long)ifindex; return XDP_REDIRECT; } @@ -4123,18 +4098,37 @@ BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u32, ifindex, if (unlikely(flags > XDP_TX)) return XDP_ABORTED; - ri->tgt_value = __xdp_map_lookup_elem(map, ifindex); + switch (map->map_type) { + case BPF_MAP_TYPE_DEVMAP: + ri->tgt_value = __dev_map_lookup_elem(map, ifindex); + ri->tgt_type = XDP_REDIR_DEV_MAP; + break; + case BPF_MAP_TYPE_DEVMAP_HASH: + ri->tgt_value = __dev_map_hash_lookup_elem(map, ifindex); + ri->tgt_type = XDP_REDIR_DEV_MAP; + break; + case BPF_MAP_TYPE_CPUMAP: + ri->tgt_value = __cpu_map_lookup_elem(map, ifindex); + ri->tgt_type = XDP_REDIR_CPU_MAP; + break; + case BPF_MAP_TYPE_XSKMAP: + ri->tgt_value = __xsk_map_lookup_elem(map, ifindex); + ri->tgt_type = XDP_REDIR_XSK_MAP; + break; + default: + ri->tgt_value = NULL; + } + if (unlikely(!ri->tgt_value)) { /* If the lookup fails we want to clear out the state in the * redirect_info struct completely, so that if an eBPF program * performs multiple lookups, the last one always takes * precedence. */ - WRITE_ONCE(ri->map, NULL); + ri->tgt_type = XDP_REDIR_UNSET; return flags; } - ri->flags = flags; ri->tgt_index = ifindex; WRITE_ONCE(ri->map, map); -- 2.27.0