B.A.T.M.A.N September 2024

b.a.t.m.a.n@lists.open-mesh.org

5 participants
9 discussions

[PATCH v5 0/2] batman-adv: increase DAT DHT timeout
by Linus Lüssing 12 Sep '24

12 Sep '24

Hi, This is the fifth itereation to increase the DAT DHT timeout to reduce the amount of broadcasted ARP Replies. To increase the timeout only for DAT DHT entries added via DHT-PUT but not for any other entry in the DAT cache the DAT cache and DAT DHT concepts are first split into two separate hash tables (PATCH 1/2). PATCH 2/2 then increases the timeout for DAT DHT entries from 5 to 30 minutes. The motivation for this patchset is based on the observations made here: https://www.open-mesh.org/projects/batman-adv/wiki/DAT_DHCP_Snooping In tests this year at Freifunk Lübeck with ~180 mesh nodes and Gluon this reduced the ARP broadcast overhead, measured over 7 days, as follows: - Total: 6677.66 bits/s -> 677.26 bits/s => -89.86% 11.92 pkts/s -> 1.21 pkts/s => -89.85% - from gateways: 5618.02 bits/s -> 212.28 => -96.22% 10.03 pkts/s -> 0.38 pkts/s => -96.21% Also see graphics and a few more test details here: - https://www.open-mesh.org/projects/batman-adv/wiki/DAT_DHCP_Snooping#Result… These patches have been applied in this mesh network without issues for 3 months now. Regards, Linus --- Changelog v5: - rebased to current main branch -> removed now obsolete debugfs code Changelog v4: - rebased to: acfc9a214d01695 ("batman-adv: genetlink: make policy common to family") Changelog v3: formerly: "batman-adv: Increase purge timeout on DAT DHT candidates" https://patchwork.open-mesh.org/patch/17728/ - fixed the potential jiffies overflow and jiffies initialization issues by replacing the last_dht_update timeout variable with a split of DAT cache and DAT DHT into two separate hash tables -> instead of maintaining two timeouts in one DAT entry two DAT entries are created and maintained in their respective DAT cache and DAT DHT hash tables Changelog v2: formerly: "batman-adv: Increase DHCP snooped DAT entry purge timeout in DHT" (https://patchwork.open-mesh.org/patch/17364/) - removed the extended timeouts flag in the DHT-PUT messages introduced in v1 again - removed DHCP dependency

2 5

[PATCH v2] batctl: add dat_dht command
by Linus Lüssing 11 Sep '24

11 Sep '24

This adds a dat_dht command to query the DHT part of DAT in batman-adv. Signed-off-by: Linus Lüssing <linus.luessing(a)c0d3.blue> --- Changelog v2: - rebased to current main branch: -> removed now obsolete debugfs code Makefile | 2 + README.rst | 27 +++++++++- batadv_packet.h | 4 +- batman_adv.h | 5 ++ dat_cache.c | 2 +- dat_dht.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++++ dat_dht_json.c | 20 ++++++++ man/batctl.8 | 6 +++ 8 files changed, 194 insertions(+), 3 deletions(-) create mode 100644 dat_dht.c create mode 100644 dat_dht_json.c diff --git a/Makefile b/Makefile index c1212c444971..92f84e5bf012 100755 --- a/Makefile +++ b/Makefile @@ -47,6 +47,8 @@ $(eval $(call add_command,bridge_loop_avoidance,y)) $(eval $(call add_command,claimtable,y)) $(eval $(call add_command,dat_cache,y)) $(eval $(call add_command,dat_cache_json,y)) +$(eval $(call add_command,dat_dht,y)) +$(eval $(call add_command,dat_dht_json,y)) $(eval $(call add_command,distributed_arp_table,y)) $(eval $(call add_command,elp_interval,y)) $(eval $(call add_command,event,y)) diff --git a/README.rst b/README.rst index 3495fba02e0e..dc1852068e0d 100644 --- a/README.rst +++ b/README.rst @@ -278,7 +278,32 @@ Usage:: Example:: - Distributed ARP Table (bat0): + Distributed ARP Table Cache (bat0): + IPv4 MAC last-seen + * 172.100.0.1 b6:9b:d0:ea:b1:13 0:00 + +where + +IPv4: + is the IP address of a client in the mesh network +MAC: + is the MAC address associated to that IP +last-seen: + is the amount of time since last refresh of this entry + + +batctl dat_dht +================= + +display the local D.A.T. DHT + +Usage:: + + batctl dat_dht|dd + +Example:: + + Distributed ARP Table DHT (bat0): IPv4 MAC last-seen * 172.100.0.1 b6:9b:d0:ea:b1:13 0:00 diff --git a/batadv_packet.h b/batadv_packet.h index 6e25753015df..93df068b00f3 100644 --- a/batadv_packet.h +++ b/batadv_packet.h @@ -60,13 +60,15 @@ enum batadv_packettype { * @BATADV_P_DATA: user payload * @BATADV_P_DAT_DHT_GET: DHT request message * @BATADV_P_DAT_DHT_PUT: DHT store message - * @BATADV_P_DAT_CACHE_REPLY: ARP reply generated by DAT + * @BATADV_P_DAT_CACHE_REPLY: deprecated: use BATADV_P_DAT_DHT_REPLY instead + * @BATADV_P_DAT_DHT_REPLY: ARP reply generated by DAT */ enum batadv_subtype { BATADV_P_DATA = 0x01, BATADV_P_DAT_DHT_GET = 0x02, BATADV_P_DAT_DHT_PUT = 0x03, BATADV_P_DAT_CACHE_REPLY = 0x04, + BATADV_P_DAT_DHT_REPLY = 0x04, }; /* this file is included by batctl which needs these defines */ diff --git a/batman_adv.h b/batman_adv.h index 35dc016c9bb4..9498ccb09d67 100644 --- a/batman_adv.h +++ b/batman_adv.h @@ -613,6 +613,11 @@ enum batadv_nl_commands { */ BATADV_CMD_SET_VLAN, + /** + * @BATADV_CMD_GET_DAT_DHT: Query list of DAT DHT entries + */ + BATADV_CMD_GET_DAT_DHT, + /* add new commands above here */ /** diff --git a/dat_cache.c b/dat_cache.c index 8d471718e4b3..d34375563aad 100644 --- a/dat_cache.c +++ b/dat_cache.c @@ -106,7 +106,7 @@ static int netlink_print_dat_cache(struct state *state, char *orig_iface, char *header; int ret; - ret = asprintf(&header, "Distributed ARP Table (%s):\n%s\n", + ret = asprintf(&header, "Distributed ARP Table Cache (%s):\n%s\n", state->mesh_iface, " IPv4 MAC VID last-seen"); diff --git a/dat_dht.c b/dat_dht.c new file mode 100644 index 000000000000..b9619ec00a73 --- /dev/null +++ b/dat_dht.c @@ -0,0 +1,131 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) B.A.T.M.A.N. contributors: + * + * Marek Lindner <mareklindner(a)neomailbox.ch> + * + * License-Filename: LICENSES/preferred/GPL-2.0 + */ + +#include <arpa/inet.h> +#include <netinet/if_ether.h> +#include <netinet/in.h> +#include <netlink/netlink.h> +#include <netlink/genl/genl.h> +#include <netlink/genl/ctrl.h> +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <sys/socket.h> + +#include "batadv_packet.h" +#include "batman_adv.h" +#include "bat-hosts.h" +#include "debug.h" +#include "functions.h" +#include "main.h" +#include "netlink.h" + +static const int dat_dht_mandatory[] = { + BATADV_ATTR_DAT_CACHE_IP4ADDRESS, + BATADV_ATTR_DAT_CACHE_HWADDRESS, + BATADV_ATTR_DAT_CACHE_VID, + BATADV_ATTR_LAST_SEEN_MSECS, +}; + +static int dat_dht_callback(struct nl_msg *msg, void *arg) +{ + int last_seen_msecs, last_seen_secs, last_seen_mins; + struct nlattr *attrs[BATADV_ATTR_MAX+1]; + struct nlmsghdr *nlh = nlmsg_hdr(msg); + struct print_opts *opts = arg; + struct bat_host *bat_host; + struct genlmsghdr *ghdr; + struct in_addr in_addr; + uint8_t *hwaddr; + int16_t vid; + char *addr; + + if (!genlmsg_valid_hdr(nlh, 0)) { + fputs("Received invalid data from kernel.\n", stderr); + exit(1); + } + + ghdr = nlmsg_data(nlh); + + if (ghdr->cmd != BATADV_CMD_GET_DAT_DHT) + return NL_OK; + + if (nla_parse(attrs, BATADV_ATTR_MAX, genlmsg_attrdata(ghdr, 0), + genlmsg_len(ghdr), batadv_netlink_policy)) { + fputs("Received invalid data from kernel.\n", stderr); + exit(1); + } + + if (missing_mandatory_attrs(attrs, dat_dht_mandatory, + ARRAY_SIZE(dat_dht_mandatory))) { + fputs("Missing attributes from kernel\n", stderr); + exit(1); + } + + in_addr.s_addr = nla_get_u32(attrs[BATADV_ATTR_DAT_CACHE_IP4ADDRESS]); + addr = inet_ntoa(in_addr); + hwaddr = nla_data(attrs[BATADV_ATTR_DAT_CACHE_HWADDRESS]); + vid = nla_get_u16(attrs[BATADV_ATTR_DAT_CACHE_VID]); + + last_seen_msecs = nla_get_u32(attrs[BATADV_ATTR_LAST_SEEN_MSECS]); + last_seen_mins = last_seen_msecs / 60000; + last_seen_msecs = last_seen_msecs % 60000; + last_seen_secs = last_seen_msecs / 1000; + + if (opts->read_opt & MULTICAST_ONLY && !(addr[0] & 0x01)) + return NL_OK; + + if (opts->read_opt & UNICAST_ONLY && (addr[0] & 0x01)) + return NL_OK; + + printf(" * %15s ", addr); + + bat_host = bat_hosts_find_by_mac((char *)hwaddr); + if (!(opts->read_opt & USE_BAT_HOSTS) || !bat_host) + printf("%02x:%02x:%02x:%02x:%02x:%02x ", + hwaddr[0], hwaddr[1], hwaddr[2], + hwaddr[3], hwaddr[4], hwaddr[5]); + else + printf("%17s ", bat_host->name); + + printf("%4i %6i:%02i\n", + BATADV_PRINT_VID(vid), last_seen_mins, last_seen_secs); + + return NL_OK; +} + +static int netlink_print_dat_dht(struct state *state, char *orig_iface, + int read_opts, float orig_timeout, + float watch_interval) +{ + char *header; + int ret; + + ret = asprintf(&header, "Distributed ARP Table DHT (%s):\n%s\n", + state->mesh_iface, + " IPv4 MAC VID last-seen"); + + if (ret < 0) + return ret; + + ret = netlink_print_common(state, orig_iface, read_opts, + orig_timeout, watch_interval, header, + BATADV_CMD_GET_DAT_DHT, + dat_dht_callback); + + free(header); + return ret; +} + +static struct debug_table_data batctl_debug_table_dat_dht = { + .netlink_fn = netlink_print_dat_dht, +}; + +COMMAND_NAMED(DEBUGTABLE, dat_dht, "dd", handle_debug_table, + COMMAND_FLAG_MESH_IFACE | COMMAND_FLAG_NETLINK, + &batctl_debug_table_dat_dht, ""); diff --git a/dat_dht_json.c b/dat_dht_json.c new file mode 100644 index 000000000000..43eb3c586d74 --- /dev/null +++ b/dat_dht_json.c @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) B.A.T.M.A.N. contributors: + * + * Linus Lüssing <linus.luessing(a)c0d3.blue> + * + * License-Filename: LICENSES/preferred/GPL-2.0 + */ + +#include "main.h" + +#include "genl_json.h" + +static struct json_query_data batctl_json_query_dat_dht = { + .nlm_flags = NLM_F_DUMP, + .cmd = BATADV_CMD_GET_DAT_DHT, +}; + +COMMAND_NAMED(JSON_MIF, dat_dht_json, "ddj", handle_json_query, + COMMAND_FLAG_MESH_IFACE | COMMAND_FLAG_NETLINK, + &batctl_json_query_dat_dht, ""); diff --git a/man/batctl.8 b/man/batctl.8 index b5be0b801708..417f5412c885 100644 --- a/man/batctl.8 +++ b/man/batctl.8 @@ -388,6 +388,10 @@ The local and global translation tables also support the "\-u" and "\-m" option [\fBmeshif\fP \fInetdev\fP] \fBdat_cache\fP|\fBdc\fP [\fB-n\fP] [\fB-H\fP] [\fB-w\fP \fIinterval\fP] (compile time option) .TP +.TP +[\fBmeshif\fP \fInetdev\fP] \fBdat_dht\fP|\fBdd\fP [\fB-n\fP] [\fB-H\fP] [\fB-w\fP \fIinterval\fP] +(compile time option) +.TP [\fBmeshif\fP \fInetdev\fP] \fBgateways\fP|\fBgwl\fP [\fB-n\fP] [\fB-H\fP] [\fB-w\fP \fIinterval\fP] .TP [\fBmeshif\fP \fInetdev\fP] \fBmcast_flags\fP|\fBmf\fP [\fB-n\fP] [\fB-H\fP] [\fB-w\fP \fIinterval\fP] @@ -416,6 +420,8 @@ the freeform debug tables or the native netlink messages. .TP [\fBmeshif\fP \fInetdev\fP] \fBdat_cache_json\fP|\fBdcj\fP .TP +[\fBmeshif\fP \fInetdev\fP] \fBdat_dht_json\fP|\fBdcj\fP +.TP [\fBmeshif\fP \fInetdev\fP] \fBgateways_json\fP|\fBgwj\fP .TP \fBhardif\fP \fIhardif\fP \fBhardif_json\fP|\fBhj\fP -- 2.45.2

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[PATCH v3] batctl: Dynamically select header format in netlink_print_neighbors
by Noah Peterson 10 Sep '24

10 Sep '24

From: Noah Peterson <NoahBPeterson1997(a)gmail.com> The netlink_print_neighbors() function previously used a static header format, which did not account for variations between the neighbor list output from different BATMAN routing algorithms (BATMAN_IV vs. BATMAN_V). This change ensures that the table header output in `batctl n` is accurate for both BATMAN routing algorithms. Signed-off-by: Noah Peterson <noahbpeterson1997(a)gmail.com> --- v3: Correcting commit message and newlines, noted by Sven <sven(a)narfation.org> v2: Changing output based on BATMAN routing algorithm, noted by Sven <sven(a)narfation.org> This patch introduces a dynamic header selection mechanism that adjusts the output format based on the active routing algorithm: - For BATMAN_IV, the header is set to "IF Neighbor last-seen". - For BATMAN_V, it changes to " Neighbor last-seen speed IF". --- neighbors.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/neighbors.c b/neighbors.c index 3102b0e..f34952b 100644 --- a/neighbors.c +++ b/neighbors.c @@ -6,6 +6,7 @@ * License-Filename: LICENSES/preferred/GPL-2.0 */ +#include <errno.h> #include <net/if.h> #include <netinet/if_ether.h> #include <netlink/netlink.h> @@ -119,9 +120,28 @@ static int netlink_print_neighbors(struct state *state, char *orig_iface, int read_opts, float orig_timeout, float watch_interval) { + char *header = NULL; + char *info_header; + + /* only parse routing algorithm name */ + last_err = -EINVAL; + info_header = netlink_get_info(state, BATADV_CMD_GET_ORIGINATORS, NULL); + free(info_header); + + if (strlen(algo_name_buf) == 0) + return last_err; + + if (!strcmp("BATMAN_IV", algo_name_buf)) + header = "IF Neighbor last-seen\n"; + if (!strcmp("BATMAN_V", algo_name_buf)) + header = " Neighbor last-seen speed IF\n"; + + if (!header) + return -EINVAL; + return netlink_print_common(state, orig_iface, read_opts, orig_timeout, watch_interval, - "IF Neighbor last-seen\n", + header, BATADV_CMD_GET_NEIGHBORS, neighbors_callback); } -- 2.39.3 (Apple Git-146)

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[PATCH v3] alfred: add more verbose error message
by Noah Peterson 10 Sep '24

10 Sep '24

From: Noah Peterson <NoahBPeterson1997(a)gmail.com> There is an issue with some Linux distributions where network interfaces are up and active, but do not have the correct link-local address. This condition is now checked and output to stderr to better help users troubleshoot this issue. Signed-off-by: Noah Peterson <noahbpeterson1997(a)gmail.com> --- v3: Add changelog, change newlines, noted by Sven <sven(a)narfation.org> v2: Fixed IPv6 address string, noted by Sven <sven(a)narfation.org> --- netsock.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/netsock.c b/netsock.c index feed21d..95dbf5e 100644 --- a/netsock.c +++ b/netsock.c @@ -21,6 +21,7 @@ #include <sys/types.h> #include <stdlib.h> #include <sys/epoll.h> +#include <arpa/inet.h> #ifdef CONFIG_ALFRED_CAPABILITIES #include <sys/capability.h> #endif @@ -322,7 +323,19 @@ static int netsock_open(struct globals *globals, struct interface *interface) enable_raw_bind_capability(0); if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) { - perror("can't bind"); + char ipstr_buf[INET6_ADDRSTRLEN]; + const char *ipstr; + + ipstr = inet_ntop(AF_INET6, &interface->address.ipv6.s6_addr, + ipstr_buf, INET6_ADDRSTRLEN); + + if (errno == EADDRNOTAVAIL) + fprintf(stderr, "can't bind to interface %s; " + "expected ipv6 address not found: %s\n", + interface->interface, + ipstr); + else + perror("can't bind"); goto err; } -- 2.39.3 (Apple Git-146)

1 0

[PATCH v2] batctl: Dynamically select header format in netlink_print_neighbors
by noahbpeterson1997＠gmail.com 10 Sep '24

10 Sep '24

The netlink_print_neighbors() function previously used a static header format, which did not account for variations between the neighbor list output from different BATMAN routing algorithms (BATMAN_IV vs. BATMAN_V). This patch introduces a dynamic header selection mechanism that adjusts the output format based on the active routing algorithm: - For BATMAN_IV, the header is set to "IF Neighbor last-seen". - For BATMAN_V, it changes to " Neighbor last-seen speed IF". This change ensures that the table header output in `batctl n` is accurate for both BATMAN routing algorithms. Signed-off-by: Noah Peterson <noahbpeterson1997(a)gmail.com> --- neighbors.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/neighbors.c b/neighbors.c index 3102b0e..f34952b 100644 --- a/neighbors.c +++ b/neighbors.c @@ -6,6 +6,7 @@ * License-Filename: LICENSES/preferred/GPL-2.0 */ +#include <errno.h> #include <net/if.h> #include <netinet/if_ether.h> #include <netlink/netlink.h> @@ -119,9 +120,28 @@ static int netlink_print_neighbors(struct state *state, char *orig_iface, int read_opts, float orig_timeout, float watch_interval) { + char *header = NULL; + char *info_header; + + /* only parse routing algorithm name */ + last_err = -EINVAL; + info_header = netlink_get_info(state, BATADV_CMD_GET_ORIGINATORS, NULL); + free(info_header); + + if (strlen(algo_name_buf) == 0) + return last_err; + + if (!strcmp("BATMAN_IV", algo_name_buf)) + header = "IF Neighbor last-seen\n"; + if (!strcmp("BATMAN_V", algo_name_buf)) + header = " Neighbor last-seen speed IF\n"; + + if (!header) + return -EINVAL; + return netlink_print_common(state, orig_iface, read_opts, orig_timeout, watch_interval, - "IF Neighbor last-seen\n", + header, BATADV_CMD_GET_NEIGHBORS, neighbors_callback); }

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[PATCH v2] alfred: add more verbose error message
by noahbpeterson1997＠gmail.com 10 Sep '24

10 Sep '24

There is an issue with some Linux distributions where network interfaces are up and active, but do not have the correct link-local address. This condition is now checked and output to stderr to help better users troubleshoot this issue. Signed-off-by: Noah Peterson noahbpeterson1997(a)gmail.com --- netsock.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/netsock.c b/netsock.c index feed21d..a3101df 100644 --- a/netsock.c +++ b/netsock.c @@ -21,6 +21,7 @@ #include <sys/types.h> #include <stdlib.h> #include <sys/epoll.h> +#include <arpa/inet.h> #ifdef CONFIG_ALFRED_CAPABILITIES #include <sys/capability.h> #endif @@ -321,8 +322,19 @@ static int netsock_open(struct globals *globals, struct interface *interface) } enable_raw_bind_capability(0); + if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) { - perror("can't bind"); + char ipstr_buf[INET6_ADDRSTRLEN]; + const char *ipstr; + ipstr = inet_ntop(AF_INET6, &interface->address.ipv6.s6_addr, + ipstr_buf, INET6_ADDRSTRLEN); + if (errno == EADDRNOTAVAIL) + fprintf(stderr, "can't bind to interface %s; " + "expected ipv6 address not found: %s\n", + interface->interface, + ipstr); + else + perror("can't bind"); goto err; }

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[PATCH] batctl: neighbor: Fix print neighbors table header
by noahbpeterson1997＠gmail.com 09 Sep '24

09 Sep '24

netlink_print_neighbors() now prints the correct header to match what batman-advanced currently outputs. The examples in the README.rst are updated too. Signed-off-by: Noah Peterson <noahbpeterson1997(a)gmail.com> --- README.rst | 6 +++--- neighbors.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/README.rst b/README.rst index 3495fba..5eda1d3 100644 --- a/README.rst +++ b/README.rst @@ -376,9 +376,9 @@ Usage:: Example:: - IF Neighbor last-seen - enp0s1 16:7b:3c:c2:bf:b8 4.612s - enp0s1 ae:1b:bf:52:25:58 0.740s + Neighbor last-seen speed IF + 16:7b:3c:c2:bf:b8 4.612s ( 1000.0) [ enp0s1] + ae:1b:bf:52:25:58 0.740s ( 1000.0) [ enp0s1] batctl originators diff --git a/neighbors.c b/neighbors.c index 3102b0e..9dcdb81 100644 --- a/neighbors.c +++ b/neighbors.c @@ -121,7 +121,7 @@ static int netlink_print_neighbors(struct state *state, char *orig_iface, { return netlink_print_common(state, orig_iface, read_opts, orig_timeout, watch_interval, - "IF Neighbor last-seen\n", + " Neighbor last-seen speed IF\n", BATADV_CMD_GET_NEIGHBORS, neighbors_callback); }

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[PATCH] alfred: add more verbose error message
by noahbpeterson1997＠gmail.com 09 Sep '24

09 Sep '24

There is an issue with some Linux distributions (Raspian) where network interfaces are up and active, but do not have the correct link-local address. This condition is now checked and output to stderr to better help users troubleshoot this issue. Signed-off-by: Noah Peterson noahbpeterson1997(a)gmail.com --- netsock.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/netsock.c b/netsock.c index feed21d..04f95c7 100644 --- a/netsock.c +++ b/netsock.c @@ -322,7 +322,23 @@ static int netsock_open(struct globals *globals, struct interface *interface) enable_raw_bind_capability(0); if (bind(sock, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) { - perror("can't bind"); + if (errno == EADDRNOTAVAIL) + fprintf(stderr, "can't bind to interface %s; " + "expected ipv6 address not found: " + "%02x%02x::%02x%02x:%02x%02x:%02x%02x:%02x%02x\n", + interface->interface, + (int)interface->address.ipv6.s6_addr[0], + (int)interface->address.ipv6.s6_addr[1], + (int)interface->address.ipv6.s6_addr[8], + (int)interface->address.ipv6.s6_addr[9], + (int)interface->address.ipv6.s6_addr[10], + (int)interface->address.ipv6.s6_addr[11], + (int)interface->address.ipv6.s6_addr[12], + (int)interface->address.ipv6.s6_addr[13], + (int)interface->address.ipv6.s6_addr[14], + (int)interface->address.ipv6.s6_addr[15]); + else + perror("can't bind"); goto err; }

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Re: bat0 not capable of MTU > 1500
by Rich Chase 03 Sep '24

03 Sep '24

I am trying to create an unimpeded path MTU of 1500 on my OpenWRT router (Belkin RT-3200). I built the firmware from git Master, with kernel version 6.1, and batman-adv version 2023.2. I have a batmesh hard-if device mastering an 802.1S mesh, which are both set to MTU=2304. Using Luci (OpenWRT web gui for uci), I set the MTU of bat0 to 1504 to accommodate .1q vlans on bat0 -- bat0.5, bat0.110, etc. I see in the system log: kern.err kernel: [751585.375855] bat0: mtu greater than device maximum Also, if I do: #> ip link set bat0 mtu 1504 I get: ip: SIOCSIFMTU: Invalid argument and if I test: #> ip link show bat0 ...it says that my mtu is 1500 still. For my life I can't see anything I'm doing wrong. Why can't bat0 have MTU greater than 1500? I don't have any other devices mastered by bat0, other than my .1s wifi mesh link. Throwing myself at your mercy. Help?

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B.A.T.M.A.N September 2024