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* tcp: Reset ACK_FROM_TAP_DUE flag only as needed, update timerStefano Brivio2023-02-121-14/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | David reports that TCP transfers might stall, especially with smaller socket buffer sizes, because we reset the ACK_FROM_TAP_DUE flag, in tcp_tap_handler(), whenever we receive an ACK segment, regardless of its sequence number and the fact that we might still be waiting for one. This way, we might fail to re-transmit frames on ACK timeouts. We need, instead, to: - indicate with the @retrans field only re-transmissions for the same data sequences. If we make progress, it should be reset, given that it's used to abort a connection when we exceed a given number of re-transmissions for the same data - unset the ACK_FROM_TAP_DUE flag if and only if the acknowledged sequence is the same as the last one we sent, as suggested by David - keep it set otherwise, if progress was done but not all the data we sent was acknowledged, and update the expiration of the ACK timeout Add a new helper for these purposes, tcp_update_seqack_from_tap(). To extend the ACK timeout, the new helper sets the ACK_FROM_TAP_DUE flag, even if it was already set, and conn_flag_do() triggers a timer update. This part should be revisited at a later time, because, strictly speaking, ACK_FROM_TAP_DUE isn't a flag anymore. One possibility might be to introduce another connection attribute for events affecting timer deadlines. Reported-by: David Gibson <david@gibson.dropbear.id.au> Link: https://bugs.passt.top/show_bug.cgi?id=41 Suggested-by: David Gibson <david@gibson.dropbear.id.au> Fixes: be5bbb9b0681 ("tcp: Rework timers to use timerfd instead of periodic bitmap scan") Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Use abstracted tap headerDavid Gibson2023-01-231-55/+30
| | | | | | | | | Update the TCP code to use the tap layer abstractions for initializing and updating the L2 and lower headers. This will make adding other tap backends in future easier. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Consolidate calculation of total frame sizeDavid Gibson2023-01-231-19/+16
| | | | | | | | | | | | | tcp_l2_buf_fill_headers() returns the size of the generated frame including the ethernet header. The caller then adds on the size of the vnet_len field to get the total frame size to be passed to the tap device. Outside the tap code, though, we never care about the ethernet header size only the final total size we need to put into an iovec. So, consolidate the total frame size calculation within tcp_l2_buf_fill_headers(). Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Remove redundant and incorrect initialization from *_iov_init()David Gibson2023-01-231-6/+2
| | | | | | | | | | tcp_sock[46]_iov_init() initialize the length of each iovec buffer to MSS_DEFAULT. That will always be overwritten before use in tcp_data_to_tap, so it's redundant. It also wasn't correct, because it didn't correctly account for the header lengths in all cases. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util: Parameterize ethernet header initializer macroDavid Gibson2023-01-231-4/+4
| | | | | | | | | We have separate IPv4 and IPv6 versions of a macro to construct an initializer for ethernet headers. However, now that we have htons_constant it's easy to simply paramterize this with the ethernet protocol number. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, udp: Use named field initializers in iov_init functionsDavid Gibson2023-01-231-14/+12
| | | | | | | | | | Both the TCP and UDP iov_init functions have some large structure literals defined in "field order" style. These are pretty hard to read since it's not obvious what value corresponds to what field. Use named field style initializers instead to make this clearer. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tap, tcp: Move tap send path to tap.cDavid Gibson2023-01-231-81/+4
| | | | | | | | | | The functions which do the final steps of sending TCP packets on through the tap interface - tcp_l2_buf_flush*() - no longer have anything that's actually specific to TCP in them, other than comments and names. Move them all to tap.c. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Combine two parts of pasta tap send path togetherDavid Gibson2023-01-231-22/+18
| | | | | | | | | | | tcp_l2_buf_flush() open codes the loop across each frame in a group, but but calls tcp_l2_buf_write_one() to send each frame to the pasta tuntap device. Combine these two pasta-specific operations into tcp_l2_buf_flush_pasta() which is a little cleaner and will enable further cleanups. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Improve interface to tcp_l2_buf_flush()David Gibson2023-01-231-37/+26
| | | | | | | | | | Currently this takes a msghdr, but the only thing we actually care about in there is the io vector. Make it take an io vector directly. We also have a weird side effect of zeroing @buf_used. Just pass this by value and zero it in the caller instead. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Don't compute total bytes in a message until we need itDavid Gibson2023-01-231-35/+18
| | | | | | | | | | | | | | | | | | | tcp[46]_l2_buf_bytes keep track of the total number of bytes we have queued to send to the tap interface. tcp_l2_buf_flush_passt() uses this to determine if sendmsg() has sent all the data we requested, or whether we need to resend a trailing portion. However, the logic for finding where we're up to in the case of a short sendmsg() can equally well tell whether we've had one at all, without knowing the total number in advance. This does require an extra loop after each sendmsg(), but it's doing simple arithmetic on values we've already been accessing, and it leads to overall simpler code. tcp[46]_l2_flags_buf_bytes were being calculated, but never used for anything, so simply remove them. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Combine two parts of passt tap send path togetherDavid Gibson2023-01-231-8/+12
| | | | | | | | | | | tcp_l2_buf_flush() open codes the "primary" send of message to the passt tap interface, but calls tcp_l2_buf_flush_part() to handle the case of a short send. Combine these two passt-specific operations into tcp_l2_buf_flush_passt() which is a little cleaner and will enable furrther cleanups. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pcap: Replace pcapm() with pcap_multiple()David Gibson2023-01-231-1/+2
| | | | | | | | | | | | | | | | | | pcapm() captures multiple frames from a msghdr, however the only thing it cares about in the msghdr is the list of buffers, where it assumes there is one frame to capture per buffer. That's what we want for its single caller but it's not the only obvious choice here (one frame per msghdr would arguably make more sense in isolation). In addition pcapm() has logic that only makes sense in the context of the passt specific path its called from: it skips the first 4 bytes of each buffer, because those have the qemu vnet_len rather than the frame proper. Make this clearer by replacing pcapm() with pcap_multiple() which more explicitly takes one struct iovec per frame, and parameterizes how much of each buffer to skip (i.e. the offset of the frame within the buffer). Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Explicitly check option length field values in tcp_opt_get()Stefano Brivio2023-01-051-0/+4
| | | | | | | | | | | | | Reported by Coverity (CWE-606, Untrusted loop bound), and actually harmless because we'll exit the option-scanning loop if the remaining length is not enough for a new option, instead of reading past the header. In any case, it looks like a good idea to explicitly check for reasonable values of option lengths. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* tcp: Pass union tcp_conn pointer to destroy and splice timer functionsStefano Brivio2022-11-251-8/+9
| | | | | | | | | | | | The pointers are actually the same, but we later pass the container union to tcp_table_compact(), which might zero the size of the whole union, and this confuses Coverity Scan. Given that we have pointers to the container union to start with, just pass those instead, all the way down to tcp_table_compact(). Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* tcp: Use dual stack sockets for port forwarding when possibleDavid Gibson2022-11-251-2/+12
| | | | | | | | | | | | | | | | Platforms like Linux allow IPv6 sockets to listen for IPv4 connections as well as native IPv6 connections. By doing this we halve the number of listening sockets we need for TCP (assuming passt/pasta is listening on the same ports for IPv4 and IPv6). When forwarding many ports (e.g. -t all) this can significantly reduce the amount of kernel memory that passt consumes. When forwarding all TCP and UDP ports for both IPv4 and IPv6 (-t all -u all), this reduces kernel memory usage from ~677MiB to ~487MiB (kernel version 6.0.8 on Fedora 37, x86_64). Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Consolidate tcp_sock_init[46]David Gibson2022-11-251-35/+15
| | | | | | | | | Previous cleanups mean that tcp_sock_init4() and tcp_sock_init6() are almost identical, and the remaining differences can be easily parameterized. Combine both into a single tcp_sock_init_af() function. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: NAT IPv4-mapped IPv6 addresses like IPv4 addressesDavid Gibson2022-11-251-36/+31
| | | | | | | | | | | | | | | | | | | passt usually doesn't NAT, but it does do so for the remapping of the gateway address to refer to the host. Currently we perform this NAT with slightly different rules on both IPv4 addresses and IPv6 addresses, but not on IPv4-mapped IPv6 addresses. This means we won't correctly handle the case of an IPv4 connection over an IPv6 socket, which is possible on Linux (and probably other platforms). Refactor tcp_conn_from_sock() to perform the NAT after converting either address family into an inany_addr, so IPv4 and and IPv4-mapped addresses have the same representation. With two new helpers this lets us remove the IPv4 and IPv6 specific paths from tcp_conn_from_sock(). Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Remove v6 flag from tcp_epoll_refDavid Gibson2022-11-251-6/+4
| | | | | | | | | | | | | | | | | | | This bit in the TCP specific epoll reference indicates whether the connection is IPv6 or IPv4. However the sites which refer to it are already calling accept() which (optionally) returns an address for the remote end of the connection. We can use the sa_family field in that address to determine the connection type independent of the epoll reference. This does have a cost: for the spliced case, it means we now need to get that address from accept() which introduces an extran copy_to_user(). However, in future we want to allow handling IPv4 connectons through IPv6 sockets, which means we won't be able to determine the IP version at the time we create the listening socket and epoll reference. So, at some point we'll have to pay this cost anyway. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Fix small errors in tcp_seq_init() time handlingDavid Gibson2022-11-251-2/+2
| | | | | | | | | | | | | | | | | | | It looks like tcp_seq_init() is supposed to advance the sequence number by one every 32ns. However we only right shift the ns part of the timespec not the seconds part, meaning that we'll advance by an extra 32 steps on each second. I don't know if that's exploitable in any way, but it doesn't appear to be the intent, nor what RFC 6528 suggests. In addition, we convert from seconds to nanoseconds with a multiplication by '1E9'. In C '1E9' is a floating point constant, forcing a conversion to floating point and back for what should be an integer calculation (confirmed with objdump and Makefile default compiler flags). Spell out 1000000000 in full to avoid that. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Have tcp_seq_init() take its parameters from struct tcp_connDavid Gibson2022-11-251-26/+10
| | | | | | | | | | | tcp_seq_init() takes a number of parameters for the connection, but at every call site, these are already populated in the tcp_conn structure. Likewise we always store the result into the @seq_to_tap field. Use this to simplify tcp_seq_init(). Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Unify initial sequence number calculation for IPv4 and IPv6David Gibson2022-11-251-28/+18
| | | | | | | | | | | | | tcp_seq_init() has separate paths for IPv4 and IPv6 addresses, which means we will calculate different sequence numbers for IPv4 and equivalent IPv4-mapped IPv6 addresses. Change it to treat these the same by always converting the input address into an inany_addr representation and use that to calculate the sequence number. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Simplify tcp_hash_match() to take an inany_addrDavid Gibson2022-11-251-12/+4
| | | | | | | | | | | tcp_hash_match() can take either an IPv4 (struct in_addr) or IPv6 (struct in6_addr) address. It has two different paths for each of those cases. However, its only caller has already constructed an equivalent inany representation of the address, so we can have tcp_hash_match take that directly and use a simpler comparison with the inany_equals() helper. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Take tcp_hash_insert() address from struct tcp_connDavid Gibson2022-11-251-12/+5
| | | | | | | | | | | | | tcp_hash_insert() takes an address to control which hash bucket the connection will go into. However, an inany_addr representation of that address is already stored in struct tcp_conn. Now that we've made the hashing of IPv4 and IPv4-mapped IPv6 addresses equivalent, we can simplify tcp_hash_insert() to use the address in struct tcp_conn, rather than taking it as an extra parameter. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Hash IPv4 and IPv4-mapped-IPv6 addresses the sameDavid Gibson2022-11-251-34/+18
| | | | | | | | | | | | | | | | | In the tcp_conn structure, we represent the address with an inany_addr which could be an IPv4 or IPv6 address. However, we have different paths which will calculate different hashes for IPv4 and equivalent IPv4-mapped IPv6 addresses. This will cause problems for some future changes. Make the hash function work the same for these two cases, by taking an inany_addr directly. Since this represents IPv4 and IPv4-mapped IPv6 addresses the same way, it will trivially hash the same for both cases. Callers are changed to construct an inany_addr from whatever they have. Some of that will be elided in later changes. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* inany: Helper functions for handling addresses which could be IPv4 or IPv6David Gibson2022-11-251-45/+43
| | | | | | | | | | | | | | struct tcp_conn stores an address which could be IPv6 or IPv4 using a union. We can do this without an additional tag by encoding IPv4 addresses as IPv4-mapped IPv6 addresses. This approach is useful wider than the specific place in tcp_conn, so expose a new 'union inany_addr' like this from a new inany.h. Along with that create a number of helper functions to make working with these "inany" addresses easier. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Don't store hash bucket in connection structuresDavid Gibson2022-11-251-5/+24
| | | | | | | | | | | | | | | Currently when we insert a connection into the hash table, we store its bucket number so we can find it when removing entries. However, we can recompute the hash value from other contents of the structure so we don't need to store it. This brings the size of tcp_tap_conn down to 64 bytes again, which means it will fit in a single cacheline on common machines. This change also removes a non-obvious constraint that the hash table have less than twice TCP_MAX_CONNS buckets, because of the way TCP_HASH_BUCKET_BITS was constructed. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Remove splice from tcp_epoll_refDavid Gibson2022-11-251-26/+34
| | | | | | | | | | | | Currently the epoll reference for tcp sockets includes a bit indicating whether the socket maps to a spliced connection. However, the reference also has the index of the connection structure which also indicates whether it is spliced. We can therefore avoid the splice bit in the epoll_ref by unifying the first part of the non-spliced and spliced handlers where we look up the connection state. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Use the same sockets to listen for spliced and non-spliced connectionsDavid Gibson2022-11-251-96/+31
| | | | | | | | | | | | | | | | | | | | In pasta mode, tcp_sock_init[46]() create separate sockets to listen for spliced connections (these are bound to localhost) and non-spliced connections (these are bound to the host address). This introduces a subtle behavioural difference between pasta and passt: by default, pasta will listen only on a single host address, whereas passt will listen on all addresses (0.0.0.0 or ::). This also prevents us using some additional optimizations that only work with the unspecified (0.0.0.0 or ::) address. However, it turns out we don't need to do this. We can splice a connection if and only if it originates from the loopback address. Currently we ensure this by having the "spliced" listening sockets listening only on loopback. Instead, defer the decision about whether to splice a connection until after accept(), by checking if the connection was made from the loopback address. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Unify part of spliced and non-spliced conn_from_sock pathDavid Gibson2022-11-251-23/+45
| | | | | | | | | | | | | | In tcp_sock_handler() we split off to handle spliced sockets before checking anything else. However the first steps of the "new connection" path for each case are the same: allocate a connection entry and accept() the connection. Remove this duplication by making tcp_conn_from_sock() handle both spliced and non-spliced cases, with help from more specific tcp_tap_conn_from_sock and tcp_splice_conn_from_sock functions for the later stages which differ. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Separate helpers to create ns listening socketsDavid Gibson2022-11-251-44/+88
| | | | | | | | | | | | | | | | | tcp_sock_init*() can create either sockets listening on the host, or in the pasta network namespace (with @ns==1). There are, however, a number of differences in how these two cases work in practice though. "ns" sockets are only used in pasta mode, and they always lead to spliced connections only. The functions are also only ever called in "ns" mode with a NULL address and interface name, and it doesn't really make sense for them to be called any other way. Later changes will introduce further differences in behaviour between these two cases, so it makes more sense to use separate functions for creating the ns listening sockets than the regular external/host listening sockets. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Unify the IN_EPOLL flagDavid Gibson2022-11-251-5/+5
| | | | | | | | | | | | There is very little common between the tcp_tap_conn and tcp_splice_conn structures. However, both do have an IN_EPOLL flag which has the same meaning in each case, though it's stored in a different location. Simplify things slightly by moving this bit into the common header of the two structures. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Partially unify tcp_timer() and tcp_splice_timer()David Gibson2022-11-251-9/+9
| | | | | | | | | | These two functions scan all the non-splced and spliced connections respectively and perform timed updates on them. Avoid scanning the now unified table twice, by having tcp_timer scan it once calling the relevant per-connection function for each one. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Unify tcp_defer_handler and tcp_splice_defer_handler()David Gibson2022-11-251-9/+11
| | | | | | | | | | | These two functions each step through non-spliced and spliced connections respectively and clean up entries for closed connections. To avoid scanning the connection table twice, we merge these into a single function which scans the unified table and performs the appropriate sort of cleanup action on each one. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Unify spliced and non-spliced connection tablesDavid Gibson2022-11-251-20/+26
| | | | | | | | | | | | | | | | | | | | | | | Currently spliced and non-spliced connections are stored in completely separate tables, so there are completely independent limits on the number of spliced and non-spliced connections. This is a bit counter-intuitive. More importantly, the fact that the tables are separate prevents us from unifying some other logic between the two cases. So, merge these two tables into one, using the 'c.spliced' common field to distinguish between them when necessary. For now we keep a common limit of 128k connections, whether they're spliced or non-spliced, which means we save memory overall. If necessary we could increase this to a 256k or higher total, which would cost memory but give some more flexibility. For now, the code paths which need to step through all extant connections are still separate for the two cases, just skipping over entries which aren't for them. We'll improve that in later patches. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Improved helpers to update connections after movingDavid Gibson2022-11-251-7/+9
| | | | | | | | | | When we compact the connection tables (both spliced and non-spliced) we need to move entries from one slot to another. That requires some updates in the entries themselves. Add helpers to make all the necessary updates for the spliced and non-spliced cases. This will simplify later cleanups. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Add connection union typeDavid Gibson2022-11-251-0/+4
| | | | | | | | | | | | | | | | Currently, the tables for spliced and non-spliced connections are entirely separate, with different types in different arrays. We want to unify them. As a first step, create a union type which can represent either a spliced or non-spliced connection. For them to be distinguishable, the individual types need to have a common header added, with a bit indicating which type this structure is. This comes at the cost of increasing the size of tcp_tap_conn to over one (64 byte) cacheline. This isn't ideal, but it makes things simpler for now and we'll re-optimize this later. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Move connection state structures into a shared headerDavid Gibson2022-11-251-156/+50
| | | | | | | | | | | | | | | Currently spliced and non-spliced connections use completely independent tracking structures. We want to unify these, so as a preliminary step move the definitions for both variants into a new tcp_conn.h header, shared by tcp.c and tcp_splice.c. This requires renaming some #defines with the same name but different meanings between the two cases. In the process we correct some places that are slightly out of sync between the comments and the code for various event bit names. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Better helpers for converting between connection pointer and indexDavid Gibson2022-11-251-38/+45
| | | | | | | | | | | | | | The macro CONN_OR_NULL() is used to look up connections by index with bounds checking. Replace it with an inline function, which means: - Better type checking - No danger of multiple evaluation of an @index with side effects Also add a helper to perform the reverse translation: from connection pointer to index. Introduce a macro for this which will make later cleanups easier and safer. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, udp: Don't initialise IPv6/IPv4 sockets if IPv4/IPv6 are not enabledStefano Brivio2022-11-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | If we disable a given IP version automatically (no corresponding default route on host) or administratively (--ipv4-only or --ipv6-only options), we don't initialise related buffers and services (DHCP for IPv4, NDP and DHCPv6 for IPv6). The "tap" handlers will also ignore packets with a disabled IP version. However, in commit 3c6ae625101a ("conf, tcp, udp: Allow address specification for forwarded ports") I happily changed socket initialisation functions to take AF_UNSPEC meaning "any enabled IP version", but I forgot to add checks back for the "enabled" part. Reported by Paul: on a host without default IPv6 route, but IPv6 enabled, connect, using IPv6, to a port handled by pasta, which tries to send data to a tap device without initialised buffers for that IP version and exits because the resulting write() fails. Simpler way to reproduce: pasta -6 and inbound IPv4 connection, or pasta -4 and inbound IPv6 connection. Reported-by: Paul Holzinger <pholzing@redhat.com> Fixes: 3c6ae625101a ("conf, tcp, udp: Allow address specification for forwarded ports") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* tcp: Correct function comments for address typesDavid Gibson2022-11-041-6/+6
| | | | | | | | | A number of functions describe themselves as taking a pointer to 'sin_addr or sin6_addr'. Those are field names, not type names. Replace them with the correct type names, in_addr or in6_addr. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Use typing to reduce chances of IPv4 endianness errorsDavid Gibson2022-11-041-25/+23
| | | | | | | | | | | | | | | | | | | We recently corrected some errors handling the endianness of IPv4 addresses. These are very easy errors to make since although we mostly store them in network endianness, we sometimes need to manipulate them in host endianness. To reduce the chances of making such mistakes again, change to always using a (struct in_addr) instead of a bare in_addr_t or uint32_t to store network endian addresses. This makes it harder to accidentally do arithmetic or comparisons on such addresses as if they were host endian. We introduce a number of IN4_IS_ADDR_*() helpers to make it easier to directly work with struct in_addr values. This has the additional benefit of making the IPv4 and IPv6 paths more visually similar. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Don't create 'tap' socket for ports that are bound to loopback onlyStefano Brivio2022-10-151-69/+114
| | | | | | | | | | | | | | | | | | | | | If the user specifies an explicit loopback address for a port binding, we're going to use that address for the 'tap' socket, and the same exact address for the 'spliced' socket (because those are, by definition, only bound to loopback addresses). This means that the second binding will fail, and, unexpectedly, the port is forwarded, but via tap device, which means the source address in the namespace won't be a loopback address. Make it explicit under which conditions we're creating which kind of socket, by refactoring tcp_sock_init() into two separate functions for IPv4 and IPv6 and gathering those conditions at the beginning. Also, don't create spliced sockets if the user specifies explicitly a non-loopback address, those are harmless but not desired either. Fixes: 3c6ae625101a ("conf, tcp, udp: Allow address specification for forwarded ports") Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, tcp_splice: Fix port remapping for inbound, spliced connectionsStefano Brivio2022-10-151-4/+3
| | | | | | | | | | | | | | | | | | | | | | | In pasta mode, when we receive a new inbound connection, we need to select a socket that was created in the namespace to proceed and connect() it to its final destination. The existing condition might pick a wrong socket, though, if the destination port is remapped, because we'll check the bitmap of inbound ports using the remapped port (stored in the epoll reference) as index, and not the original port. Instead of using the port bitmap for this purpose, store this information in the epoll reference itself, by adding a new 'outbound' bit, that's set if the listening socket was created the namespace, and unset otherwise. Then, use this bit to pick a socket on the right side. Suggested-by: David Gibson <david@gibson.dropbear.id.au> Fixes: 33482d5bf293 ("passt: Add PASTA mode, major rework") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* tcp, tcp_splice: Adjust comments to current meaning of inbound and outboundStefano Brivio2022-10-151-1/+1
| | | | | | | | | | | | | | | | | | | | For tcp_sock_init_ns(), "inbound" connections used to be the ones being established toward any listening socket we create, as opposed to sockets we connect(). Similarly, tcp_splice_new() used to handle "inbound" connections in the sense that they originated from listening sockets, and they would in turn cause a connect() on an "outbound" socket. Since commit 1128fa03fe73 ("Improve types and names for port forwarding configuration"), though, inbound connections are more broadly defined as the ones directed to guest or namepsace, and outbound the ones originating from there. Update comments for those two functions. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* conf, tcp, udp: Allow specification of interface to bind toStefano Brivio2022-10-151-12/+15
| | | | | | | | | | | | | | | | Since kernel version 5.7, commit c427bfec18f2 ("net: core: enable SO_BINDTODEVICE for non-root users"), we can bind sockets to interfaces, if they haven't been bound yet (as in bind()). Introduce an optional interface specification for forwarded ports, prefixed by %, that can be passed together with an address. Reported use case: running local services that use ports we want to have externally forwarded: https://github.com/containers/podman/issues/14425 Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* Move logging functions to a new file, log.cStefano Brivio2022-10-141-0/+1
| | | | | | | | Logging to file is going to add some further complexity that we don't want to squeeze into util.c. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* cppcheck: Suppress NULL pointer warning in tcp_sock_consume()David Gibson2022-09-291-0/+1
| | | | | | | | | | | | | Recent versions of cppcheck give a warning due to the NULL buffer passed to recv() in tcp_sock_consume(). Since this apparently works, I assume it's actually valid, but cppcheck doesn't know that recv() can take a NULL buffer. So, use a suppression to get rid of the error. Also add an unmatchedSuppression suppression since only some cppcheck versions complain about this. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* cppcheck: Work around false positive NULL pointer dereference errorDavid Gibson2022-09-291-0/+1
| | | | | | | | | | | | | Some versions of cppcheck could errneously report a NULL pointer deference inside a sizeof(). This is now fixed in cppcheck upstream[0]. For systems using an affected version, add a suppression to work around the bug. Also add an unmatchedSuppression suppression so the suppression itself doesn't cause a warning if you *do* have a fixed cppcheck. [0] https://github.com/danmar/cppcheck/pull/4471 Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Fix widespread off-by-one error dealing with port numbersDavid Gibson2022-09-241-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Port numbers (for both TCP and UDP) are 16-bit, and so fit exactly into a 'short'. USHRT_MAX is therefore the maximum port number and this is widely used in the code. Unfortunately, a lot of those places don't actually want the maximum port number (USHRT_MAX == 65535), they want the total number of ports (65536). This leads to a number of potentially nasty consequences: * We have buffer overruns on the port_fwd::delta array if we try to use port 65535 * We have similar potential overruns for the tcp_sock_* arrays * Interestingly udp_act had the correct size, but we can calculate it in a more direct manner * We have a logical overrun of the ports bitmap as well, although it will just use an unused bit in the last byte so isnt harmful * Many loops don't consider port 65535 (which does mitigate some but not all of the buffer overruns above) * In udp_invert_portmap() we incorrectly compute the reverse port translation for return packets Correct all these by using a new NUM_PORTS defined explicitly for this purpose. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Treat port numbers as unsignedDavid Gibson2022-09-241-2/+2
| | | | | | | | | | | Port numbers are unsigned values, but we're storing them in (signed) int variables in some places. This isn't actually harmful, because int is large enough to hold the entire range of ports. However in places we don't want to use an in_port_t (usually to avoid overflow on the last iteration of a loop) it makes more conceptual sense to use an unsigned int. This will also avoid some problems with later cleanups. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 19:39:40 +0000