Author: cem Date: Thu Oct 17 20:25:15 2019 New Revision: 353696 URL: https://svnweb.freebsd.org/changeset/base/353696
Log: debugnet(4): Add optional full-duplex mode It remains unattached to any client protocol. Netdump is unaffected (remaining half-duplex). The intended consumer is NetGDB. Submitted by: John Reimer <john.reimer AT emc.com> (earlier version) Discussed with: markj Differential Revision: https://reviews.freebsd.org/D21541 Modified: head/sys/net/debugnet.c head/sys/net/debugnet.h head/sys/net/debugnet_int.h head/sys/netinet/netdump/netdump_client.c Modified: head/sys/net/debugnet.c ============================================================================== --- head/sys/net/debugnet.c Thu Oct 17 20:18:07 2019 (r353695) +++ head/sys/net/debugnet.c Thu Oct 17 20:25:15 2019 (r353696) @@ -175,7 +175,7 @@ debugnet_udp_output(struct debugnet_pcb *pcb, struct m udp = mtod(m, void *); udp->uh_ulen = htons(m->m_pkthdr.len); /* Use this src port so that the server can connect() the socket */ - udp->uh_sport = htons(pcb->dp_client_ack_port); + udp->uh_sport = htons(pcb->dp_client_port); udp->uh_dport = htons(pcb->dp_server_port); /* Computed later (protocol-dependent). */ udp->uh_sum = 0; @@ -183,6 +183,28 @@ debugnet_udp_output(struct debugnet_pcb *pcb, struct m return (debugnet_ip_output(pcb, m)); } +static int +debugnet_ack_output(struct debugnet_pcb *pcb, uint32_t seqno /* net endian */) +{ + struct debugnet_ack *dn_ack; + struct mbuf *m; + + DNETDEBUG("Acking with seqno %u\n", ntohl(seqno)); + + m = m_gethdr(M_NOWAIT, MT_DATA); + if (m == NULL) { + printf("%s: Out of mbufs\n", __func__); + return (ENOBUFS); + } + m->m_len = sizeof(*dn_ack); + m->m_pkthdr.len = sizeof(*dn_ack); + MH_ALIGN(m, sizeof(*dn_ack)); + dn_ack = mtod(m, void *); + dn_ack->da_seqno = seqno; + + return (debugnet_udp_output(pcb, m)); +} + /* * Dummy free function for debugnet clusters. */ @@ -216,6 +238,9 @@ debugnet_send(struct debugnet_pcb *pcb, uint32_t type, uint32_t i, pktlen, sent_so_far; int retries, polls, error; + if (pcb->dp_state == DN_STATE_REMOTE_CLOSED) + return (ECONNRESET); + want_acks = 0; pcb->dp_rcvd_acks = 0; retries = 0; @@ -307,6 +332,8 @@ retransmit: } debugnet_network_poll(pcb->dp_ifp); DELAY(500); + if (pcb->dp_state == DN_STATE_REMOTE_CLOSED) + return (ECONNRESET); } pcb->dp_seqno += i; return (0); @@ -316,7 +343,63 @@ retransmit: * Network input primitives. */ +/* + * Just introspect the header enough to fire off a seqno ack and validate + * length fits. + */ static void +debugnet_handle_rx_msg(struct debugnet_pcb *pcb, struct mbuf **mb) +{ + const struct debugnet_msg_hdr *dnh; + struct mbuf *m; + int error; + + m = *mb; + + if (m->m_pkthdr.len < sizeof(*dnh)) { + DNETDEBUG("ignoring small debugnet_msg packet\n"); + return; + } + + /* Get ND header. */ + if (m->m_len < sizeof(*dnh)) { + m = m_pullup(m, sizeof(*dnh)); + *mb = m; + if (m == NULL) { + DNETDEBUG("m_pullup failed\n"); + return; + } + } + dnh = mtod(m, const void *); + + if (ntohl(dnh->mh_len) + sizeof(*dnh) > m->m_pkthdr.len) { + DNETDEBUG("Dropping short packet.\n"); + 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) + 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); +} + +static void debugnet_handle_ack(struct debugnet_pcb *pcb, struct mbuf **mb, uint16_t sport) { const struct debugnet_ack *dn_ack; @@ -325,10 +408,6 @@ debugnet_handle_ack(struct debugnet_pcb *pcb, struct m m = *mb; - if (m->m_pkthdr.len < sizeof(*dn_ack)) { - DNETDEBUG("ignoring small ACK packet\n"); - return; - } /* Get Ack. */ if (m->m_len < sizeof(*dn_ack)) { m = m_pullup(m, sizeof(*dn_ack)); @@ -363,7 +442,7 @@ debugnet_handle_udp(struct debugnet_pcb *pcb, struct m { const struct udphdr *udp; struct mbuf *m; - uint16_t sport; + uint16_t sport, ulen; /* UDP processing. */ @@ -384,15 +463,39 @@ debugnet_handle_udp(struct debugnet_pcb *pcb, struct m } udp = mtod(m, const void *); - /* For now, the only UDP packets we expect to receive are acks. */ - if (ntohs(udp->uh_dport) != pcb->dp_client_ack_port) { - DNETDEBUG("not on the expected ACK port.\n"); + /* We expect to receive UDP packets on the configured client port. */ + if (ntohs(udp->uh_dport) != pcb->dp_client_port) { + DNETDEBUG("not on the expected port.\n"); return; } + + /* Check that ulen does not exceed actual size of data. */ + ulen = ntohs(udp->uh_ulen); + if (m->m_pkthdr.len < ulen) { + DNETDEBUG("ignoring runt UDP packet\n"); + return; + } + sport = ntohs(udp->uh_sport); m_adj(m, sizeof(*udp)); - debugnet_handle_ack(pcb, mb, sport); + ulen -= sizeof(*udp); + + if (ulen == sizeof(struct debugnet_ack)) { + debugnet_handle_ack(pcb, mb, sport); + return; + } + + if (pcb->dp_rx_handler == NULL) { + if (ulen < sizeof(struct debugnet_ack)) + DNETDEBUG("ignoring small ACK packet\n"); + else + DNETDEBUG("ignoring unexpected non-ACK packet on " + "half-duplex connection.\n"); + return; + } + + debugnet_handle_rx_msg(pcb, mb); } /* @@ -523,9 +626,10 @@ debugnet_connect(const struct debugnet_conn_params *dc .dp_server = dcp->dc_server, .dp_gateway = dcp->dc_gateway, .dp_server_port = dcp->dc_herald_port, /* Initially */ - .dp_client_ack_port = dcp->dc_client_ack_port, + .dp_client_port = dcp->dc_client_port, .dp_seqno = 1, .dp_ifp = dcp->dc_ifp, + .dp_rx_handler = dcp->dc_rx_handler, }; /* Switch to the debugnet mbuf zones. */ @@ -593,7 +697,7 @@ debugnet_connect(const struct debugnet_conn_params *dc serbuf, pcb->dp_server_port, (pcb->dp_gateway == INADDR_ANY) ? "" : " via ", (pcb->dp_gateway == INADDR_ANY) ? "" : gwbuf, - clibuf, pcb->dp_client_ack_port, if_name(ifp)); + clibuf, pcb->dp_client_port, if_name(ifp)); } /* Validate iface is online and supported. */ Modified: head/sys/net/debugnet.h ============================================================================== --- head/sys/net/debugnet.h Thu Oct 17 20:18:07 2019 (r353695) +++ head/sys/net/debugnet.h Thu Oct 17 20:25:15 2019 (r353696) @@ -90,6 +90,8 @@ struct debugnet_methods { #define DEBUGNET_SUPPORTED_NIC(ifp) \ ((ifp)->if_debugnet_methods != NULL && (ifp)->if_type == IFT_ETHER) +struct debugnet_pcb; /* opaque */ + /* * Debugnet consumer API. */ @@ -100,13 +102,30 @@ struct debugnet_conn_params { in_addr_t dc_gateway; uint16_t dc_herald_port; - uint16_t dc_client_ack_port; + uint16_t dc_client_port; const void *dc_herald_data; uint32_t dc_herald_datalen; -}; -struct debugnet_pcb; /* opaque */ + /* + * If NULL, debugnet is a unidirectional channel from panic machine to + * remote server (like netdump). + * + * If handler is non-NULL, packets received on the client port that are + * not just tx acks are forwarded to the provided handler. + * + * 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. + */ + void (*dc_rx_handler)(struct debugnet_pcb *, struct mbuf **); +}; /* * Open a unidirectional stream to the specified server's herald port. Modified: head/sys/net/debugnet_int.h ============================================================================== --- head/sys/net/debugnet_int.h Thu Oct 17 20:18:07 2019 (r353695) +++ head/sys/net/debugnet_int.h Thu Oct 17 20:25:15 2019 (r353696) @@ -50,6 +50,7 @@ enum dnet_pcb_st { DN_STATE_INIT = 1, DN_STATE_HAVE_GW_MAC, DN_STATE_GOT_HERALD_PORT, + DN_STATE_REMOTE_CLOSED, }; struct debugnet_pcb { @@ -67,8 +68,12 @@ struct debugnet_pcb { /* Saved driver if_input to restore on close. */ void (*dp_drv_input)(struct ifnet *, struct mbuf *); + /* RX handler for bidirectional protocols. */ + void (*dp_rx_handler)(struct debugnet_pcb *, + struct mbuf **); + enum dnet_pcb_st dp_state; - uint16_t dp_client_ack_port; + uint16_t dp_client_port; bool dp_event_started; }; Modified: head/sys/netinet/netdump/netdump_client.c ============================================================================== --- head/sys/netinet/netdump/netdump_client.c Thu Oct 17 20:18:07 2019 (r353695) +++ head/sys/netinet/netdump/netdump_client.c Thu Oct 17 20:25:15 2019 (r353696) @@ -316,7 +316,7 @@ netdump_start(struct dumperinfo *di) dcp.dc_gateway = nd_gateway.s_addr; dcp.dc_herald_port = NETDUMP_PORT; - dcp.dc_client_ack_port = NETDUMP_ACKPORT; + dcp.dc_client_port = NETDUMP_ACKPORT; dcp.dc_herald_data = nd_path; dcp.dc_herald_datalen = (nd_path[0] == 0) ? 0 : strlen(nd_path) + 1; _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
