From 48477d5802dbf426b20a74c313e5496c6291fdd2 Mon Sep 17 00:00:00 2001 From: David Lamparter Date: Thu, 10 Mar 2022 13:59:26 +0100 Subject: [PATCH 1/2] pimd: make logs useful for input drops This path here is pretty far on top of the list of issues that operators will run into and have to debug when setting up PIM. Make the log messages actually tell what's going on. Also escalate some from `debug mroute detail` to `debug mroute`. Signed-off-by: David Lamparter --- pimd/pim_mroute.c | 47 +++++++++++++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 16 deletions(-) diff --git a/pimd/pim_mroute.c b/pimd/pim_mroute.c index f1fd2ef735..8afd893fd0 100644 --- a/pimd/pim_mroute.c +++ b/pimd/pim_mroute.c @@ -161,18 +161,34 @@ int pim_mroute_msg_nocache(int fd, struct interface *ifp, const kernmsg *msg) struct pim_rpf *rpg; pim_sgaddr sg; - rpg = pim_ifp ? RP(pim_ifp->pim, msg->msg_im_dst) : NULL; + memset(&sg, 0, sizeof(sg)); + sg.src = msg->msg_im_src; + sg.grp = msg->msg_im_dst; + + if (!pim_ifp) { + if (PIM_DEBUG_MROUTE) + zlog_debug( + "%s: PIM not enabled on interface, dropping packet to %pSG", + ifp->name, &sg); + return 0; + } + + rpg = RP(pim_ifp->pim, msg->msg_im_dst); /* * If the incoming interface is unknown OR * the Interface type is SSM we don't need to * do anything here */ - if (!rpg || pim_rpf_addr_is_inaddr_any(rpg)) { - if (PIM_DEBUG_MROUTE_DETAIL) - zlog_debug( - "%s: Interface is not configured correctly to handle incoming packet: Could be !pim_ifp, !SM, !RP", - __func__); - + if (!rpg) { + if (PIM_DEBUG_MROUTE) + zlog_debug("%s: no RPF for packet to %pSG", ifp->name, + &sg); + return 0; + } + if (pim_rpf_addr_is_inaddr_any(rpg)) { + if (PIM_DEBUG_MROUTE) + zlog_debug("%s: null RPF for packet to %pSG", ifp->name, + &sg); return 0; } @@ -181,22 +197,21 @@ int pim_mroute_msg_nocache(int fd, struct interface *ifp, const kernmsg *msg) * us */ if (!pim_if_connected_to_source(ifp, msg->msg_im_src)) { - if (PIM_DEBUG_MROUTE_DETAIL) + if (PIM_DEBUG_MROUTE) zlog_debug( - "%s: Received incoming packet that doesn't originate on our seg", - __func__); + "%s: incoming packet to %pSG from non-connected source", + ifp->name, &sg); return 0; } - memset(&sg, 0, sizeof(sg)); - sg.src = msg->msg_im_src; - sg.grp = msg->msg_im_dst; - if (!(PIM_I_am_DR(pim_ifp))) { + /* unlike the other debug messages, this one is further in the + * "normal operation" category and thus under _DETAIL + */ if (PIM_DEBUG_MROUTE_DETAIL) zlog_debug( - "%s: Interface is not the DR blackholing incoming traffic for %pSG", - __func__, &sg); + "%s: not DR on interface, not forwarding traffic for %pSG", + ifp->name, &sg); /* * We are not the DR, but we are still receiving packets From 94c2ec42c4a16d037faf29b24cf89c6542744a9a Mon Sep 17 00:00:00 2001 From: David Lamparter Date: Wed, 1 Jun 2022 09:54:31 +0200 Subject: [PATCH 2/2] pimd: try to reinstall MFC when we get NOCACHE Whether due to a pimd bug, some expiry, or someone just deleting MFC entries, when we're in NOCACHE we *know* there's no MFC entry. Add an install call to make sure pimd's MFC view aligns with the actual kernel MFC. Signed-off-by: David Lamparter --- pimd/pim_mroute.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/pimd/pim_mroute.c b/pimd/pim_mroute.c index 8afd893fd0..3d15666dd6 100644 --- a/pimd/pim_mroute.c +++ b/pimd/pim_mroute.c @@ -47,6 +47,8 @@ #include "pim_msg.h" static void mroute_read_on(struct pim_instance *pim); +static int pim_upstream_mroute_update(struct channel_oil *c_oil, + const char *name); int pim_mroute_set(struct pim_instance *pim, int enable) { @@ -160,6 +162,7 @@ int pim_mroute_msg_nocache(int fd, struct interface *ifp, const kernmsg *msg) struct pim_upstream *up; struct pim_rpf *rpg; pim_sgaddr sg; + bool desync = false; memset(&sg, 0, sizeof(sg)); sg.src = msg->msg_im_src; @@ -232,6 +235,12 @@ int pim_mroute_msg_nocache(int fd, struct interface *ifp, const kernmsg *msg) up = pim_upstream_find_or_add(&sg, ifp, PIM_UPSTREAM_FLAG_MASK_FHR, __func__); + if (up->channel_oil->installed) { + zlog_warn( + "%s: NOCACHE for %pSG, MFC entry disappeared - reinstalling", + ifp->name, &sg); + desync = true; + } /* * I moved this debug till after the actual add because @@ -255,6 +264,11 @@ int pim_mroute_msg_nocache(int fd, struct interface *ifp, const kernmsg *msg) /* if we have receiver, inherit from parent */ pim_upstream_inherited_olist_decide(pim_ifp->pim, up); + /* we just got NOCACHE from the kernel, so... MFC is not in the + * kernel for some reason or another. Try installing again. + */ + if (desync) + pim_upstream_mroute_update(up->channel_oil, __func__); return 0; }