Date: Sat, 27 May 2023 16:35:44 GMT From: Bryan Drewery <bdrewery@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: b498331b037f - main - netgdb: Fix netgdb double ack, print proxy address Message-ID: <202305271635.34RGZi19032692@gitrepo.freebsd.org>
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The branch main has been updated by bdrewery: URL: https://cgit.FreeBSD.org/src/commit/?id=b498331b037f20bde90b46fc37678fbd421dcf09 commit b498331b037f20bde90b46fc37678fbd421dcf09 Author: John Reimer <John_Reimer@Dell.com> AuthorDate: 2023-05-27 02:48:14 +0000 Commit: Bryan Drewery <bdrewery@FreeBSD.org> CommitDate: 2023-05-27 16:34:17 +0000 netgdb: Fix netgdb double ack, print proxy address - Fixes netgdb's double ack - Moving ack responsibility to debugnet, decision to ack made by netdump/netgdb. - Finish responsibility moved to debugnet, new finish handler. - netgdb now prints the address to connect to in case the user doesn't have access to the proxy machine. Sponsored by: Dell EMC Reviewed By: markj, bdrewery (earlier version) Differential Revision: https://reviews.freebsd.org/D40064 --- sys/gdb/netgdb.c | 76 ++++++++++++++++++++------------------------------ sys/net/debugnet.c | 57 ++++++++++++++++++++++++++++--------- sys/net/debugnet.h | 15 +++++++++- sys/net/debugnet_int.h | 6 ++-- 4 files changed, 93 insertions(+), 61 deletions(-) diff --git a/sys/gdb/netgdb.c b/sys/gdb/netgdb.c index dc426adea766..58e02bb97d28 100644 --- a/sys/gdb/netgdb.c +++ b/sys/gdb/netgdb.c @@ -57,6 +57,7 @@ __FBSDID("$FreeBSD$"); #error "NetGDB cannot be used without DDB at this time" #endif +#include <sys/errno.h> #include <sys/param.h> #include <sys/kdb.h> #include <sys/sbuf.h> @@ -110,64 +111,27 @@ static int *netgdb_prev_kdb_inactive; /* TODO(CEM) disable ack mode */ /* - * Receive non-TX ACK packets on the client port. + * Attempt to accept the incoming packet. If we run into ENOBUFS or another + * error, return it. * - * The mbuf chain will have all non-debugnet framing headers removed - * (ethernet, inet, udp). It will start with a debugnet_msg_hdr, of - * which the header is guaranteed to be contiguous. If m_pullup is - * used, the supplied in-out mbuf pointer should be updated - * appropriately. - * - * If the handler frees the mbuf chain, it should set the mbuf pointer - * to NULL. Otherwise, the debugnet input framework will free the - * chain. + * The mbuf chain will have all framing headers removed (ethernet, inet, udp, + * debugnet). */ -static void -netgdb_rx(struct debugnet_pcb *pcb, struct mbuf **mb) +static int +netgdb_rx(struct mbuf *m) { - const struct debugnet_msg_hdr *dnh; - struct mbuf *m; uint32_t rlen, count; - int error; - - m = *mb; - dnh = mtod(m, const void *); - - if (ntohl(dnh->mh_type) == DEBUGNET_FINISHED) { - sbuf_putc(&netgdb_rxsb, CTRL('C')); - return; - } - - if (ntohl(dnh->mh_type) != DEBUGNET_DATA) { - printf("%s: Got unexpected debugnet message %u\n", - __func__, ntohl(dnh->mh_type)); - return; - } - rlen = ntohl(dnh->mh_len); + rlen = m->m_pkthdr.len; #define _SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1)) if (_SBUF_FREESPACE(&netgdb_rxsb) < rlen) { NETGDB_DEBUG("Backpressure: Not ACKing RX of packet that " "would overflow our buffer (%zd/%zd used).\n", netgdb_rxsb.s_len, netgdb_rxsb.s_size); - return; + return (ENOBUFS); } #undef _SBUF_FREESPACE - error = debugnet_ack_output(pcb, dnh->mh_seqno); - if (error != 0) { - printf("%s: Couldn't ACK rx packet %u; %d\n", __func__, - ntohl(dnh->mh_seqno), error); - /* - * Sender will re-xmit, and assuming the condition is - * transient, we'll process the packet's contentss later. - */ - return; - } - - m_adj(m, sizeof(*dnh)); - dnh = NULL; - /* * Inlined m_apply -- why isn't there a macro or inline function * version? @@ -181,6 +145,13 @@ netgdb_rx(struct debugnet_pcb *pcb, struct mbuf **mb) rlen -= count; m = m->m_next; } + return (0); +} + +static void +netgdb_finish(void) +{ + sbuf_putc(&netgdb_rxsb, CTRL('C')); } /* @@ -338,6 +309,7 @@ DB_COMMAND_FLAGS(netgdb, db_netgdb_cmd, CS_OWN) struct debugnet_ddb_config params; struct debugnet_conn_params dcp; struct debugnet_pcb *pcb; + char proxy_buf[INET_ADDRSTRLEN]; int error; if (!KERNEL_PANICKED()) { @@ -374,6 +346,7 @@ DB_COMMAND_FLAGS(netgdb, db_netgdb_cmd, CS_OWN) .dc_client_port = NETGDB_CLIENTPORT, .dc_herald_aux2 = NETGDB_PROTO_V1, .dc_rx_handler = netgdb_rx, + .dc_finish_handler = netgdb_finish, }; error = debugnet_connect(&dcp, &pcb); @@ -398,6 +371,19 @@ DB_COMMAND_FLAGS(netgdb, db_netgdb_cmd, CS_OWN) db_cmd_loop_done = 1; gdb_return_to_ddb = true; db_printf("(detaching GDB will return control to DDB)\n"); + + const in_addr_t *proxy_addr = debugnet_get_server_addr(netgdb_conn); + const uint16_t proxy_port = debugnet_get_server_port(netgdb_conn) + 1; + inet_ntop(AF_INET, proxy_addr, proxy_buf, sizeof(proxy_buf)); + if (inet_ntop(AF_INET, proxy_addr, proxy_buf, sizeof(proxy_buf)) == NULL) { + db_printf("Connected to proxy. " + "Use target remote <proxy address>:%hu to begin debugging.\n", + proxy_port); + } else { + db_printf("Connected to proxy. " + "Use target remote %s:%hu to begin debugging.\n", + proxy_buf, proxy_port); + } #if 0 /* Aspirational, but does not work reliably. */ db_printf("(ctrl-c will return control to ddb)\n"); diff --git a/sys/net/debugnet.c b/sys/net/debugnet.c index 96cd61b4dd10..cefdd4f582ce 100644 --- a/sys/net/debugnet.c +++ b/sys/net/debugnet.c @@ -115,6 +115,22 @@ debugnet_get_gw_mac(const struct debugnet_pcb *pcb) return (pcb->dp_gw_mac.octet); } +const in_addr_t * +debugnet_get_server_addr(const struct debugnet_pcb *pcb) +{ + MPASS(g_debugnet_pcb_inuse && pcb == &g_dnet_pcb && + pcb->dp_state >= DN_STATE_GOT_HERALD_PORT); + return (&pcb->dp_server); +} + +const uint16_t +debugnet_get_server_port(const struct debugnet_pcb *pcb) +{ + MPASS(g_debugnet_pcb_inuse && pcb == &g_dnet_pcb && + pcb->dp_state >= DN_STATE_GOT_HERALD_PORT); + return (pcb->dp_server_port); +} + /* * Start of network primitives, beginning with output primitives. */ @@ -365,6 +381,8 @@ debugnet_handle_rx_msg(struct debugnet_pcb *pcb, struct mbuf **mb) { const struct debugnet_msg_hdr *dnh; struct mbuf *m; + uint32_t hdr_type; + uint32_t seqno; int error; m = *mb; @@ -383,33 +401,46 @@ debugnet_handle_rx_msg(struct debugnet_pcb *pcb, struct mbuf **mb) return; } } - dnh = mtod(m, const void *); + dnh = mtod(m, const void *); if (ntohl(dnh->mh_len) + sizeof(*dnh) > m->m_pkthdr.len) { DNETDEBUG("Dropping short packet.\n"); return; } + hdr_type = ntohl(dnh->mh_type); + if (hdr_type != DEBUGNET_DATA) { + if (hdr_type == DEBUGNET_FINISHED) { + printf("Remote shut down the connection on us!\n"); + pcb->dp_state = DN_STATE_REMOTE_CLOSED; + if (pcb->dp_finish_handler != NULL) { + pcb->dp_finish_handler(); + } + } else { + DNETDEBUG("Got unexpected debugnet message %u\n", hdr_type); + } + return; + } + /* * If the issue is transient (ENOBUFS), sender should resend. If * non-transient (like driver objecting to rx -> tx from the same * thread), not much else we can do. */ - error = debugnet_ack_output(pcb, dnh->mh_seqno); - if (error != 0) + seqno = dnh->mh_seqno; /* net endian */ + m_adj(m, sizeof(*dnh)); + dnh = NULL; + error = pcb->dp_rx_handler(m); + if (error != 0) { + DNETDEBUG("RX handler was not able to accept message, error %d. " + "Skipping ack.\n", error); return; - - if (ntohl(dnh->mh_type) == DEBUGNET_FINISHED) { - printf("Remote shut down the connection on us!\n"); - pcb->dp_state = DN_STATE_REMOTE_CLOSED; - - /* - * Continue through to the user handler so they are signalled - * not to wait for further rx. - */ } - pcb->dp_rx_handler(pcb, mb); + error = debugnet_ack_output(pcb, seqno); + if (error != 0) { + DNETDEBUG("Couldn't ACK rx packet %u; %d\n", ntohl(seqno), error); + } } static void diff --git a/sys/net/debugnet.h b/sys/net/debugnet.h index 4d209df4cd8b..81962070c9e3 100644 --- a/sys/net/debugnet.h +++ b/sys/net/debugnet.h @@ -134,7 +134,10 @@ struct debugnet_conn_params { * * The handler should ACK receieved packets with debugnet_ack_output. */ - void (*dc_rx_handler)(struct debugnet_pcb *, struct mbuf **); + int (*dc_rx_handler)(struct mbuf *); + + /* Cleanup signal for bidirectional protocols. */ + void (*dc_finish_handler)(void); }; /* @@ -207,6 +210,16 @@ void debugnet_network_poll(struct debugnet_pcb *); */ const unsigned char *debugnet_get_gw_mac(const struct debugnet_pcb *); +/* + * Get the connected server address. + */ +const in_addr_t *debugnet_get_server_addr(const struct debugnet_pcb *); + +/* + * Get the connected server port. + */ +const uint16_t debugnet_get_server_port(const struct debugnet_pcb *); + /* * Callbacks from core mbuf code. */ diff --git a/sys/net/debugnet_int.h b/sys/net/debugnet_int.h index 982000248374..b6c5f2cecff1 100644 --- a/sys/net/debugnet_int.h +++ b/sys/net/debugnet_int.h @@ -69,8 +69,10 @@ struct debugnet_pcb { void (*dp_drv_input)(struct ifnet *, struct mbuf *); /* RX handler for bidirectional protocols. */ - void (*dp_rx_handler)(struct debugnet_pcb *, - struct mbuf **); + int (*dp_rx_handler)(struct mbuf *); + + /* Cleanup signal for bidirectional protocols. */ + void (*dp_finish_handler)(void); enum dnet_pcb_st dp_state; uint16_t dp_client_port;
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