| 16 | | These instructions are designed to be applied to the baseline.ndz as of Aug 25,2006. |
| 17 | | |
| 18 | | * ssh to one of the nodes |
| 19 | | {{{ |
| 20 | | joeuser@console.sb1:~$ ssh root@node1-2 |
| 21 | | }}} |
| 22 | | * open /usr/src/madwifi/trunk/net80211/ieee80211_node.c in your favourite text editor |
| 23 | | * goto line 427, you'll see some code that looks like this: |
| 24 | | {{{ |
| 25 | | if (ic->ic_flags & IEEE80211_F_DESBSSID) |
| 26 | | IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_des_bssid); |
| 27 | | else |
| 28 | | ni->ni_bssid[0] |= 0x02; /* local bit for IBSS */ |
| 29 | | }}} |
| 30 | | * Right after those lines, add these lines: |
| 31 | | {{{ |
| 32 | | int len = 0; |
| 33 | | while (ic->ic_des_essid[len] != 0) len++; |
| 34 | | int i; |
| 35 | | for (i=0;i<IEEE80211_ADDR_LEN;i++) { |
| 36 | | ni->ni_bssid[i] = ic->ic_des_essid[i % len]; |
| 37 | | } |
| 38 | | }}} |
| 39 | | * Save the file |
| 40 | | * Move to the madwifi directory and compile the changes |
| 41 | | {{{ |
| 42 | | root@node1-2:~$ cd /usr/src/madwifi/trunk |
| 43 | | root@node1-2:~$ make |
| 44 | | }}} |
| 45 | | * Copy the modified madwifi drivers to where the kernel expects them |
| 46 | | {{{ |
| 47 | | root@node1-2:~$ cp /usr/src/madwifi/trunk/net80211/*.ko /lib/modules/2.6.12/net |
| 48 | | }}} |
| 49 | | * Turn on and off the modified driver so the changes are activated |
| 50 | | {{{ |
| 51 | | root@node1-2:~$ modprobe -r ath_pci |
| 52 | | root@node1-2:~$ modprobe ath_pci |
| 53 | | }}} |
| 54 | | * Done! |
| 55 | | |
| 56 | | You will probably want to save the image of this modified node in order to save running these steps all the time. |
| 57 | | |
| 58 | | Save the image of the node: |
| 59 | | {{{ |
| 60 | | joeuser@console.sb1:~$ saveNode 1,2 |
| 61 | | }}} |
| 62 | | |
| 63 | | These instructions should be fairly similar for future version of madwifi. Look for where a node picks what bssid it wants to use (usually in create_ibss or similar), and then find that function where the node determines that it's in adhoc mode. |
| 64 | | |
| 65 | | |
| 66 | | == Changes required in madwifi-0.9.2 driver == |
| 67 | | |
| 68 | | In case you're using a more recent madwifi driver, the following might help. |
| 69 | | Assuming you've unpacked madwifi-0.9.2.tar.gz in your home directory, the file is: |
| 70 | | {{{ |
| 71 | | ~/madwifi-0.9.2/net80211/ieee80211_node.c |
| 72 | | }}} |
| 73 | | The change is roughly on line 305; before: |
| | 16 | Here's a patch of what needs to get done for madwifi-0.9.3.1. This has been added as part of [wiki:Documentation/SupportedImages/baseline-2.2.ndz baseline-2.2.ndz]: |
| 76 | | if (vap->iv_opmode == IEEE80211_M_IBSS) { |
| 77 | | vap->iv_flags |= IEEE80211_F_SIBSS; |
| | 19 | diff -Naur madwifi-0.9.3.1/net80211/ieee80211_node.c madwifi-0.9.3.1-ibss/net80211/ieee80211_node.c |
| | 20 | --- madwifi-0.9.3.1/net80211/ieee80211_node.c 2007-05-23 04:43:05.000000000 -0400 |
| | 21 | +++ madwifi-0.9.3.1-ibss/net80211/ieee80211_node.c 2007-07-03 17:17:45.000000000 -0400 |
| | 22 | @@ -53,6 +53,15 @@ |
| | 23 | #include <net80211/ieee80211_var.h> |
| | 24 | #include <net80211/if_athproto.h> |
| | 25 | |
| | 26 | +static int ibss_grid = 1; |
| | 27 | +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,52)) |
| | 28 | +MODULE_PARM(ibss_grid, "i"); |
| | 29 | +#else |
| | 30 | +#include <linux/moduleparam.h> |
| | 31 | +module_param(ibss_grid, int, 0600); |
| | 32 | +#endif |
| | 33 | +MODULE_PARM_DESC(ibss_grid, "IBSS hack based on SSID for large networks"); |
| | 34 | + |
| | 35 | /* |
| | 36 | * Association id's are managed with a bit vector. |
| | 37 | */ |
| | 38 | @@ -301,8 +310,25 @@ |
| 81 | | else |
| 82 | | ni->ni_bssid[0] |= 0x02; /* local bit for IBSS */ |
| 83 | | } |
| | 42 | - else |
| | 43 | - ni->ni_bssid[0] |= 0x02; /* local bit for IBSS */ |
| | 44 | + else { |
| | 45 | + /* XXX: If we're on a large network then hash the SSID |
| | 46 | + * instead of the MAC address to generate the BSSID. |
| | 47 | + * This ensures that nodes with identical SSIDs end |
| | 48 | + * up with identical BSSIDs, regardless of any |
| | 49 | + * timing bugs. We might be able to fix this for good |
| | 50 | + * elsewhere */ |
| | 51 | + if(ibss_grid) { |
| | 52 | + int i; |
| | 53 | + printk(KERN_INFO "net80211: IBSS BSSID " |
| | 54 | + "generation based on hash of SSID - " |
| | 55 | + "temporary fix for large networks\n"); |
| | 56 | + for(i=0; i<IEEE80211_ADDR_LEN;i++) |
| | 57 | + ni->ni_bssid[i] = ni->ni_essid[i % |
| | 58 | + ni->ni_esslen]; |
| | 59 | + } |
| | 60 | + else |
| | 61 | + ni->ni_bssid[0] |= 0x02;/* local bit for IBSS */ |
| | 62 | + } |
| | 63 | } else if (vap->iv_opmode == IEEE80211_M_AHDEMO) { |
| | 64 | if (vap->iv_flags & IEEE80211_F_DESBSSID) |
| | 65 | IEEE80211_ADDR_COPY(ni->ni_bssid, vap->iv_des_bssid); |
| 85 | | |
| 86 | | After: |
| 87 | | |
| 88 | | {{{ |
| 89 | | if (vap->iv_opmode == IEEE80211_M_IBSS) { |
| 90 | | int i; |
| 91 | | vap->iv_flags |= IEEE80211_F_SIBSS; |
| 92 | | ni->ni_capinfo |= IEEE80211_CAPINFO_IBSS; /* XXX */ |
| 93 | | if (vap->iv_flags & IEEE80211_F_DESBSSID) |
| 94 | | IEEE80211_ADDR_COPY(ni->ni_bssid, vap->iv_des_bssid); |
| 95 | | else |
| 96 | | ni->ni_bssid[0] |= 0x02; /* local bit for IBSS */ |
| 97 | | for(i=0; i<IEEE80211_ADDR_LEN;i++){ |
| 98 | | ni->ni_bssid[i] = ni->ni_essid[i % ni->ni_esslen]; |
| 99 | | } |
| 100 | | } |
| 101 | | }}} |
| 102 | | |
| 103 | | then simply make and copy the new modules as above. |
| 104 | | |
