- dev - passt

[PATCH v2] pasta, passt-repair: Support multiple events per read() in inotify handlers
by David Gibson 30 Mar '25

30 Mar '25

From: Stefano Brivio <sbrivio(a)redhat.com> The current code assumes that we'll get one event per read() on inotify descriptors, but that's not the case, not from documentation, and not from reports. Add loops in the two inotify handlers we have, in pasta-specific code and passt-repair, to go through all the events we receive. Link: https://bugs.passt.top/show_bug.cgi?id=119 Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com> [dwg: Remove unnecessary buffer expansion, use strnlen instead of strlen to make Coverity happier] Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- passt-repair.c | 27 ++++++++++++++++++++------- pasta.c | 20 +++++++++++++------- 2 files changed, 33 insertions(+), 14 deletions(-) diff --git a/passt-repair.c b/passt-repair.c index 120f7aa7..d36c9c94 100644 --- a/passt-repair.c +++ b/passt-repair.c @@ -111,14 +111,14 @@ int main(int argc, char **argv) } if ((sb.st_mode & S_IFMT) == S_IFDIR) { - char buf[sizeof(struct inotify_event) + NAME_MAX + 1]; + char buf[sizeof(struct inotify_event) + NAME_MAX + 1] + __attribute__ ((aligned(__alignof__(struct inotify_event)))); const struct inotify_event *ev; char path[PATH_MAX + 1]; + bool found = false; ssize_t n; int fd; - ev = (struct inotify_event *)buf; - if ((fd = inotify_init1(IN_CLOEXEC)) < 0) { fprintf(stderr, "inotify_init1: %i\n", errno); _exit(1); @@ -130,6 +130,8 @@ int main(int argc, char **argv) } do { + char *p; + n = read(fd, buf, sizeof(buf)); if (n < 0) { fprintf(stderr, "inotify read: %i", errno); @@ -138,11 +140,22 @@ int main(int argc, char **argv) if (n < (ssize_t)sizeof(*ev)) { fprintf(stderr, "Short inotify read: %zi", n); - _exit(1); + continue; + } + + for (p = buf; p < buf + n; p += sizeof(*ev) + ev->len) { + ev = (const struct inotify_event *)p; + + if (ev->len >= REPAIR_EXT_LEN && + !memcmp(ev->name + + strnlen(ev->name, ev->len) - + REPAIR_EXT_LEN, + REPAIR_EXT, REPAIR_EXT_LEN)) { + found = true; + break; + } } - } while (ev->len < REPAIR_EXT_LEN || - memcmp(ev->name + strlen(ev->name) - REPAIR_EXT_LEN, - REPAIR_EXT, REPAIR_EXT_LEN)); + } while (!found); snprintf(path, sizeof(path), "%s/%s", argv[1], ev->name); if ((stat(path, &sb))) { diff --git a/pasta.c b/pasta.c index fa3e7de5..017fa322 100644 --- a/pasta.c +++ b/pasta.c @@ -498,17 +498,23 @@ void pasta_netns_quit_init(const struct ctx *c) */ void pasta_netns_quit_inotify_handler(struct ctx *c, int inotify_fd) { - char buf[sizeof(struct inotify_event) + NAME_MAX + 1]; - const struct inotify_event *in_ev = (struct inotify_event *)buf; + char buf[sizeof(struct inotify_event) + NAME_MAX + 1] + __attribute__ ((aligned(__alignof__(struct inotify_event)))); + const struct inotify_event *ev; + ssize_t n; + char *p; - if (read(inotify_fd, buf, sizeof(buf)) < (ssize_t)sizeof(*in_ev)) + if ((n = read(inotify_fd, buf, sizeof(buf))) < (ssize_t)sizeof(*ev)) return; - if (strncmp(in_ev->name, c->netns_base, sizeof(c->netns_base))) - return; + for (p = buf; p < buf + n; p += sizeof(*ev) + ev->len) { + ev = (const struct inotify_event *)p; - info("Namespace %s is gone, exiting", c->netns_base); - _exit(EXIT_SUCCESS); + if (!strncmp(ev->name, c->netns_base, sizeof(c->netns_base))) { + info("Namespace %s is gone, exiting", c->netns_base); + _exit(EXIT_SUCCESS); + } + } } /** -- 2.49.0

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[PATCH v2 0/2] udp: Fix some minor warts in the ICMP error propagation code
by David Gibson 28 Mar '25

28 Mar '25

While working on using connected sockets for both sides of UDP flows, I spotted a couple of minor problems in the recently added ICMP error propagation code. Here are the fixes. v2: * Rebase and fix conflict with Jon's recent fix in the same code David Gibson (2): udp: Don't attempt to forward ICMP socket errors to other sockets udp: Improve name of UDP related ICMP sending functions udp.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-) -- 2.49.0

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[RFC PATCH] pasta, passt-repair: Support multiple events per read() in inotify handlers
by Stefano Brivio 28 Mar '25

28 Mar '25

The current code assumes that we'll get one event per read() on inotify descriptors, but that's not the case, not from documentation, and not from reports. Add loops in the two inotify handlers we have, in pasta-specific code and passt-repair, to go through all the events we receive. While in pasta the the inotify watch is in an epoll list, and we'll get epoll wakeups as long as there's data to read, in passt-repair that's not the case. So, in pasta we can simply size the buffer for a single event and try to read one, but in passt-repair, we'll need to size the buffer to a safer, reasonable amount of events. Link: https://bugs.passt.top/show_bug.cgi?id=119 Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com> --- I'm posting this as RFC because, while it seems to do the job and I tested all the code paths, Coverity isn't amused by the fact that we assume that inotify 'name' attributes (ev->name) are NULL-terminated. They actually are, but the code is not very robust. Addressing that is kind of trivial but I keep getting it wrong, so I'll start posting this and fix that up later (direct fixes/edits of this patch are also welcome, of course). passt-repair.c | 26 +++++++++++++++++++------- pasta.c | 20 +++++++++++++------- 2 files changed, 32 insertions(+), 14 deletions(-) diff --git a/passt-repair.c b/passt-repair.c index 120f7aa..86581c6 100644 --- a/passt-repair.c +++ b/passt-repair.c @@ -111,14 +111,14 @@ int main(int argc, char **argv) } if ((sb.st_mode & S_IFMT) == S_IFDIR) { - char buf[sizeof(struct inotify_event) + NAME_MAX + 1]; + char buf[(sizeof(struct inotify_event) + NAME_MAX + 1) * 128] + __attribute__ ((aligned(__alignof__(struct inotify_event)))); const struct inotify_event *ev; char path[PATH_MAX + 1]; + bool found = false; ssize_t n; int fd; - ev = (struct inotify_event *)buf; - if ((fd = inotify_init1(IN_CLOEXEC)) < 0) { fprintf(stderr, "inotify_init1: %i\n", errno); _exit(1); @@ -130,6 +130,8 @@ int main(int argc, char **argv) } do { + char *p; + n = read(fd, buf, sizeof(buf)); if (n < 0) { fprintf(stderr, "inotify read: %i", errno); @@ -138,11 +140,21 @@ int main(int argc, char **argv) if (n < (ssize_t)sizeof(*ev)) { fprintf(stderr, "Short inotify read: %zi", n); - _exit(1); + continue; + } + + for (p = buf; p < buf + n; p += sizeof(*ev) + ev->len) { + ev = (const struct inotify_event *)p; + + if (ev->len >= REPAIR_EXT_LEN && + !memcmp(ev->name + strlen(ev->name) - + REPAIR_EXT_LEN, + REPAIR_EXT, REPAIR_EXT_LEN)) { + found = true; + break; + } } - } while (ev->len < REPAIR_EXT_LEN || - memcmp(ev->name + strlen(ev->name) - REPAIR_EXT_LEN, - REPAIR_EXT, REPAIR_EXT_LEN)); + } while (!found); snprintf(path, sizeof(path), "%s/%s", argv[1], ev->name); if ((stat(path, &sb))) { diff --git a/pasta.c b/pasta.c index fa3e7de..017fa32 100644 --- a/pasta.c +++ b/pasta.c @@ -498,17 +498,23 @@ void pasta_netns_quit_init(const struct ctx *c) */ void pasta_netns_quit_inotify_handler(struct ctx *c, int inotify_fd) { - char buf[sizeof(struct inotify_event) + NAME_MAX + 1]; - const struct inotify_event *in_ev = (struct inotify_event *)buf; + char buf[sizeof(struct inotify_event) + NAME_MAX + 1] + __attribute__ ((aligned(__alignof__(struct inotify_event)))); + const struct inotify_event *ev; + ssize_t n; + char *p; - if (read(inotify_fd, buf, sizeof(buf)) < (ssize_t)sizeof(*in_ev)) + if ((n = read(inotify_fd, buf, sizeof(buf))) < (ssize_t)sizeof(*ev)) return; - if (strncmp(in_ev->name, c->netns_base, sizeof(c->netns_base))) - return; + for (p = buf; p < buf + n; p += sizeof(*ev) + ev->len) { + ev = (const struct inotify_event *)p; - info("Namespace %s is gone, exiting", c->netns_base); - _exit(EXIT_SUCCESS); + if (!strncmp(ev->name, c->netns_base, sizeof(c->netns_base))) { + info("Namespace %s is gone, exiting", c->netns_base); + _exit(EXIT_SUCCESS); + } + } } /** -- 2.43.0

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[PATCH v2 0/2] udp: add guest-to-remote traceroute
by Jon Maloy 28 Mar '25

28 Mar '25

We add support for UDP traceroute in the tap-sock direction. More will follow when this one is settled. --- v2: - Added ttl/hop_limit as flow selection criteria - Using ancillary data instead of setsockopt() to pass on ttl/hop_limit. - Added support for IPv6 Jon Maloy (2): Add ttl to outgoing flow structure lookups udp: support traceroute with udp flow.c | 17 ++++++++++++----- flow.h | 8 ++++++-- flow_table.h | 3 ++- icmp.c | 15 ++++++++++----- icmp.h | 2 +- packet.h | 2 ++ tap.c | 25 ++++++++++++++++++------- tcp.c | 6 +++--- udp.c | 31 +++++++++++++++++++++++++++---- udp.h | 3 ++- udp_flow.c | 7 ++++--- udp_flow.h | 2 +- 12 files changed, 88 insertions(+), 33 deletions(-) -- 2.48.1

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[PATCH v2] udp: correct source address for ICMP messages
by Jon Maloy 27 Mar '25

27 Mar '25

While developing traceroute forwarding tap-to-sock we found that struct msghdr.msg_name for the ICMPs in the opposite direction always contains the destination address of the original UDP message, and not, as one might expect, the one of the host which created the error message. Study of the kernel code reveals that this address instead is appended as extra data after the received struct sock_extended_err area. We now change the ICMP receive code accordingly. Fixes: 55431f0077b6 ("udp: create and send ICMPv4 to local peer when applicable") Fixes: 68b04182e07d ("udp: create and send ICMPv6 to local peer when applicable") Signed-off-by: Jon Maloy <jmaloy(a)redhat.com> --- v2: Removed stray comment and unecessary initializations, as per feedback from David Gibson --- udp.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/udp.c b/udp.c index 80520cb..9d16529 100644 --- a/udp.c +++ b/udp.c @@ -510,10 +510,13 @@ static void udp_send_conn_fail_icmp6(const struct ctx *c, */ static int udp_sock_recverr(const struct ctx *c, union epoll_ref ref) { - const struct sock_extended_err *ee; + struct errhdr { + struct sock_extended_err ee; + union sockaddr_inany saddr; + }; + const struct errhdr *eh; const struct cmsghdr *hdr; - union sockaddr_inany saddr; - char buf[CMSG_SPACE(sizeof(*ee))]; + char buf[CMSG_SPACE(sizeof(struct errhdr))]; char data[ICMP6_MAX_DLEN]; int s = ref.fd; struct iovec iov = { @@ -521,8 +524,6 @@ static int udp_sock_recverr(const struct ctx *c, union epoll_ref ref) .iov_len = sizeof(data) }; struct msghdr mh = { - .msg_name = &saddr, - .msg_namelen = sizeof(saddr), .msg_iov = &iov, .msg_iovlen = 1, .msg_control = buf, @@ -553,7 +554,7 @@ static int udp_sock_recverr(const struct ctx *c, union epoll_ref ref) return -1; } - ee = (const struct sock_extended_err *)CMSG_DATA(hdr); + eh = (const struct errhdr *)CMSG_DATA(hdr); if (ref.type == EPOLL_TYPE_UDP_REPLY) { flow_sidx_t sidx = flow_sidx_opposite(ref.flowside); const struct flowside *toside = flowside_at_sidx(sidx); @@ -561,18 +562,19 @@ static int udp_sock_recverr(const struct ctx *c, union epoll_ref ref) if (hdr->cmsg_level == IPPROTO_IP) { dlen = MIN(dlen, ICMP4_MAX_DLEN); - udp_send_conn_fail_icmp4(c, ee, toside, saddr.sa4.sin_addr, + udp_send_conn_fail_icmp4(c, &eh->ee, toside, + eh->saddr.sa4.sin_addr, data, dlen); } else if (hdr->cmsg_level == IPPROTO_IPV6) { - udp_send_conn_fail_icmp6(c, ee, toside, - &saddr.sa6.sin6_addr, + udp_send_conn_fail_icmp6(c, &eh->ee, toside, + &eh->saddr.sa6.sin6_addr, data, dlen, sidx.flowi); } } else { trace("Ignoring received IP_RECVERR cmsg on listener socket"); } debug("%s error on UDP socket %i: %s", - str_ee_origin(ee), s, strerror_(ee->ee_errno)); + str_ee_origin(&eh->ee), s, strerror_(eh->ee.ee_errno)); return 1; } -- 2.48.1

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[PATCH v2 0/7] UDP flow socket preliminaries
by David Gibson 27 Mar '25

27 Mar '25

As discussed on our recent call, I'm working towards using connected sockets on both sides of UDP flows. This series makes some preliminary reworks that simplify things and make that easier. v2: * Added patches 5..7, other patches unchanged. David Gibson (7): udp: Common invocation of udp_sock_errs() for vhost-user and "buf" paths udp: Simplify checking of epoll event bits udp_vu: Factor things out of udp_vu_reply_sock_data() loop udp: Share more logic between vu and non-vu reply socket paths udp: Better handling of failure to forward from reply socket udp: Always hash socket facing flowsides udp: Add helper function for creating connected UDP socket udp.c | 121 +++++++++++++++++++++-------------------- udp_flow.c | 143 ++++++++++++++++++++++++++----------------------- udp_internal.h | 2 +- udp_vu.c | 68 +++++++---------------- udp_vu.h | 9 ++-- 5 files changed, 166 insertions(+), 177 deletions(-) -- 2.49.0

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[PATCH 0/2] udp: Fix some minor warts in the ICMP error propagation code
by David Gibson 26 Mar '25

26 Mar '25

While working on using connected sockets for both sides of UDP flows, I spotted a couple of minor problems in the recently added ICMP error propagation code. Here are the fixes. David Gibson (2): udp: Don't attempt to forward ICMP socket errors to other sockets udp: Improve name of UDP related ICMP sending functions udp.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) -- 2.49.0

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RE: [PATCH] build: normalize arm targets
by Julian Wundrak 26 Mar '25

26 Mar '25

Thanks Stefano, Sorry for this stupid error and the overhead. --- Von: "Stefano Brivio" <sbrivio(a)redhat.com> An: "Julian Wundrak" <julian(a)wundrak.net> Cc: "undefined" <passt-dev(a)passt.top> Gesendet: Mittwoch, 26. März 2025 21:45 Betreff: Re: [PATCH] build: normalize arm targets On Wed, 26 Mar 2025 21:29:02 +0100 Stefano Brivio wrote: > Hi Julian, > > On Wed, 26 Mar 2025 20:14:31 +0000 > Julian Wundrak wrote: > > > Linux distributions use different dumpmachine outputs for the ARM > > architecture. arm, armv6l, armv7l. > > For the syscall annotation, these variants are standardized to “arm”. > > > > Signed-off-by: Julian Wundrak > > --- > > Hey everyone, > > > > This resolves bug #117. > > I hope I did everything correctly, because this is the first time I have > > had to submit a patch via git send emails. > > Then you got it right on the first attempt! I'll just add a tag in the > commit message: > > Link: https://bugs.passt.top/show_bug.cgi?id=117 > > ...and I'll run tests, then apply it. ...almost: you forgot to fix this as you mentioned in: https://bugs.passt.top/show_bug.cgi?id=117#c3 I'm fixing it up on merge as it's a trivial typo. -- Stefano

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[PATCH] build: normalize arm targets
by Julian Wundrak 26 Mar '25

26 Mar '25

Linux distributions use different dumpmachine outputs for the ARM architecture. arm, armv6l, armv7l. For the syscall annotation, these variants are standardized to “arm”. Signed-off-by: Julian Wundrak <julian(a)wundrak.net> --- Hey everyone, This resolves bug #117. I hope I did everything correctly, because this is the first time I have had to submit a patch via git send emails. Julian Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/Makefile b/Makefile index 31cbac3..1b83234 100644 --- a/Makefile +++ b/Makefile @@ -20,6 +20,7 @@ $(if $(TARGET),,$(error Failed to get target architecture)) # Get 'uname -m'-like architecture description for target TARGET_ARCH := $(firstword $(subst -, ,$(TARGET))) TARGET_ARCH := $(patsubst [:upper:],[:lower:],$(TARGET_ARCH)) +TARGET_ARCH := $(patsubst arm%,arm,$(TARGET)) TARGET_ARCH := $(subst powerpc,ppc,$(TARGET_ARCH)) # On some systems enabling optimization also enables source fortification, -- 2.49.0

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[PATCH] build: normalize arm targets
by Julian Wundrak 26 Mar '25

26 Mar '25

Linux distributions use different dumpmachine outputs for the ARM architecture. arm, armv6l, armv7l. For the syscall annotation, these variants are standardized to “arm”. Signed-off-by: Julian Wundrak <julian(a)wundrak.net> --- Argh, same problem with target instead of target_arch as in comment. I squashed it, but I'm not sure, how this works with the mails. Sorry for the overhead! Julian Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/Makefile b/Makefile index 31cbac3..3328f83 100644 --- a/Makefile +++ b/Makefile @@ -20,6 +20,7 @@ $(if $(TARGET),,$(error Failed to get target architecture)) # Get 'uname -m'-like architecture description for target TARGET_ARCH := $(firstword $(subst -, ,$(TARGET))) TARGET_ARCH := $(patsubst [:upper:],[:lower:],$(TARGET_ARCH)) +TARGET_ARCH := $(patsubst arm%,arm,$(TARGET_ARCH)) TARGET_ARCH := $(subst powerpc,ppc,$(TARGET_ARCH)) # On some systems enabling optimization also enables source fortification, -- 2.49.0

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